Grammar and mechanics · hard · v4.6.1

GRM-02

Spell out abbreviations and acronyms on first use in body copy and help content. Use the short form for subsequent mentions. Universally understood abbreviations (FAQ, URL, ZIP, LLC, IRS) and regulated accessibility terms (TTY) do not require expansion in any context. Internal or organization-specific abbreviations should always be expanded on a public-facing page. If the surrounding copy acknowledges the reader may not know a term, expand it.

Pass example

We use single sign-on (SSO) across all products. SSO keeps your account secure.

Fail example

If you don't know an HMO from an HSA, you're not alone.

Relevant content types

Sources

Style guides that shaped this standard. Each is listed on /sources with its license and opt-out path.

  • Mailchimp

Version history

  1. v4.6.1 · 2026-04-23

    Per-standard version tracking introduced. Every standard starts at the library version current at introduction; bump per-standard when the rule text, examples, or content_type_notes change.

Related standards

Other standards in the Grammar and mechanics category.

  • GRM-01 — Use the serial comma (Oxford comma) in lists of three or more items.
  • GRM-03 — Use exclamation points sparingly. Never use more than one at a time, and never in error messages or alerts.
  • GRM-04 — Don't use ampersands in body copy unless they are part of a brand name. Ampersands are acceptable in headings, navigation labels, footer links, and other space-constrained UI elements where '&' is a conventional shorthand.
  • GRM-05 — Use numerals for numbers in body copy. Spell out a number only when it begins a sentence.
  • GRM-06 — Hyphenate number-unit compound modifiers before nouns. The unit takes singular form when hyphenated.

← The content model