A Working Glossary and Resource List for ERP Buyers

Every ERP shortlist conversation eventually stalls on vocabulary. Someone on the evaluation team says "we need clean SoD before go-live" or asks whether the vendor's MRP engine handles phantom BOMs, and half the room nods without being fully sure what was just said. This is a working glossary for people actually evaluating ERP software, plus pointers to where you can check a vendor's claims against real customer experience instead of a sales deck.

Core Terms You Need Before Sitting Through a Demo

These are not dictionary definitions. Each one includes what actually goes wrong when a buyer does not understand the term.

Financial and Accounting Terms

• Chart of Accounts (CoA): The hierarchical list of every account a company uses to record financial transactions: assets, liabilities, equity, revenue, and expenses, each with a unique code. A poorly designed CoA (too flat, inconsistent numbering, no segment for department or location) is one of the most common reasons ERP data migrations run over budget, because someone has to remap thousands of historical transactions to a new structure. Fix the CoA design before migration starts, not during it.
• General Ledger (GL): The central record that stores every financial transaction posted by every module. Accounts payable, accounts receivable, inventory, and payroll all flow into the GL. When a vendor says their system has "real-time GL posting," they mean transactions hit the ledger immediately rather than in a nightly batch job, which matters if the finance team needs same-day visibility.
• Segregation of Duties (SoD): A control principle stating no single person should be able to both initiate and approve a transaction. The person who creates a new vendor record should not also be able to approve payments to that vendor, for example. Auditors check for SoD violations specifically, and ERP systems enforce it through role-based permissions. Weak SoD configuration is a recurring finding in audits at companies that rushed their ERP rollout.

Manufacturing and Supply Chain Terms

• Material Requirements Planning (MRP): The calculation engine that looks at sales orders and forecasts, checks current inventory and open purchase orders, then works backward through the bill of materials to determine what to buy or build, and when. MRP is the historical origin of the "ERP" acronym; the term literally evolved from it in the 1990s once vendors bolted finance and HR onto MRP II systems.
• Bill of Materials (BOM): The recipe for a manufactured item: every component, sub-assembly, and raw material required to build one unit, plus quantities. A "phantom BOM" is a sub-assembly that exists in the BOM structure for costing and planning purposes but is never actually stocked or built as a standalone item. MRP engines handle these differently, so it is worth asking a vendor directly whether phantom BOMs are supported rather than assuming they are.
• Available to Promise (ATP) and Capable to Promise (CTP): ATP tells a sales rep whether existing inventory can cover a new order by a given date. CTP goes further and factors in production capacity, checking whether the factory can actually build enough units in time rather than just whether raw stock exists. Systems that only calculate ATP will overpromise delivery dates in make-to-order environments.

Deployment and Architecture Terms

• Single-tenant vs. multi-tenant: In a multi-tenant SaaS ERP, every customer runs on the same shared application codebase, with data logically separated, and upgrades roll out to everyone at once on the vendor's schedule. Single-tenant means a company has its own dedicated instance, allowing more customization and control over upgrade timing, but it usually costs more and puts more upgrade work on the internal team.
• Two-tier ERP: Running a large ERP suite such as SAP or Oracle at corporate headquarters while subsidiaries or smaller divisions run a lighter, cheaper ERP like NetSuite or Business Central that syncs up to the corporate system. Common at companies with a mix of large mature business units and smaller or newly acquired ones.
• Configuration vs. customization: Configuration means changing settings within what the vendor already built: field visibility, approval workflows, report layouts. Customization means writing new code that does not exist in the base product. Configuration survives upgrades cleanly; customization often has to be re-tested or rebuilt after every major version update. A useful question for any vendor demo is simply whether a feature being shown is configuration or a custom build.
• Middleware / iPaaS: Integration platform as a service, tools like Celigo, Workato, or Boomi that move data between an ERP and other systems (an e-commerce platform, a CRM, an EDI connection with a large retail customer) without custom point-to-point code. Worth budgeting for separately, since it is rarely included in the base ERP license.

Verifying What a Vendor Tells You

Sales reps are paid to close deals, not to volunteer where their product struggles. Cross-check every major claim against independent sources before signing anything.

Peer review platforms, with G2, Capterra, and Gartner Peer Insights being the three most established, collect verified customer reviews with filters for company size, industry, and department. Do not just look at the aggregate star rating; filter to companies of similar size in a similar industry, since a five-star review from a 3,000-employee retailer says little about how a product handles a 60-person distributor's needs. Read the negative reviews specifically, looking for patterns. Three unrelated reviewers all mentioning slow support response times is a signal. One angry review is noise.

Watch for review-drive artifacts. A cluster of five-star reviews posted within the same two-week window, written in similar language, often means a vendor ran an internal campaign asking customers to leave reviews (sometimes in exchange for a gift card) rather than organic feedback accumulating naturally over time. That does not make the product bad, but it means that batch should be discounted and reviews outside the cluster should carry more weight.

Analyst reports, Gartner's Magic Quadrant and Forrester Wave being the best known, evaluate vendors on completeness of vision and ability to execute, but they are built primarily for large-enterprise buyers, and full access often costs money. Many vendors will share a complimentary copy of a report they are named in; it is reasonable to ask a sales rep directly.

Industry Associations Worth Knowing

ASCM, the Association for Supply Chain Management formed from the 2018 merger of APICS with other supply chain bodies, runs the CPIM and CSCP certification programs that most experienced supply chain and planning professionals hold. If a consultant or internal candidate lists CPIM on a resume, it signals formal training in MRP, inventory management, and production planning concepts, not just familiarity with a particular software's buttons.

The Institute of Finance and Management (IOFM) and the Institute of Management Accountants (IMA) are worth knowing on the finance side, particularly for an evaluation that touches accounts payable automation or cost accounting redesign.

Major vendor conferences, including NetSuite's SuiteWorld, Microsoft's Business Applications events, and SAP's Sapphire, are heavily sales-oriented, but they are useful for one thing specifically: the customer panel sessions, where existing users rather than vendor staff describe their actual implementation experience. Skipping the keynote in favor of customer-run breakout sessions is usually a better use of conference time.

Buying Process Terms

• RFP (Request for Proposal): A formal document sent to shortlisted vendors describing requirements, asking them to respond with pricing, implementation approach, and how their product handles specific scenarios. Skipping a written RFP in favor of informal demos usually means the eventual comparison between vendors is based on whoever gave the slickest presentation rather than a consistent set of answers to the same questions.
• TCO (Total Cost of Ownership): The full cost of a system over a defined period, usually three to five years: license or subscription fees, implementation services, integration middleware, training, and ongoing internal administration time. Vendors quote list price. Buyers need TCO to compare offers that look similar on a pricing page but carry very different implementation and maintenance costs.
• UAT (User Acceptance Testing): The phase before go-live where the people who will actually use the system daily, not the IT team or the implementation consultants, test it against real scenarios pulled from their own work. A rushed or skipped UAT phase is one of the most reliable predictors of a rocky go-live.
• Cutover: The defined window when a company stops using the old system and starts using the new one, including the final data sync and the point of no return for rolling back. A clear cutover plan specifies exactly what happens if something breaks in the first 48 hours.

Verifying Vendor Claims Beyond Reviews

Published case studies on a vendor's own website are marketing material, curated to show the best outcomes. Ask instead for two or three reference calls with existing customers in a similar industry and size range, and come to those calls with specific questions rather than general ones: how long did data migration actually take versus the original estimate, what module ended up needing customization that wasn't expected, and what would they do differently if starting over. A vendor unwilling to arrange any reference calls at all is worth treating with more skepticism than one whose references give a mixed but honest picture.

This Site's Tools

Before serious pricing conversations start, it helps to have a defensible ballpark rather than a vendor's optimistic estimate. The site's own TCO calculator is built for exactly that stage, giving a rough multi-year cost picture that a budget committee can react to before contract negotiations even begin.