Est. is a documented abbreviation with more than one common expansion. The page distinguishes meaning, capitalization, and punctuation rather than presenting one context-free rule.
ReviewedEvidence1 sourceSectionWriting & Style
Quick answer
“Est.” can mean “estimated” or “established.” Use context to make the meaning clear, and do not confuse it with uppercase “EST” for Eastern Standard Time.
Key details
Core IssueEst. is used as a written abbreviation for “estimated” and “established”; the same letters without the same punctuation/case can also have other meanings such as Eastern Standard Time.
Phrase Roleabbreviation mechanics
Registergeneral and business writing
Important caveats
Ambiguity Boundary
Uppercase EST can mean Eastern Standard Time, so context and capitalization can change the interpretation.
Style Boundary
Use the form required by the document or house style; the abbreviation does not have one meaning in every context.
Further guidance
Meaning
Cambridge records est. for both “estimated” and “established.”
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
Approx./approx. are documented shortened forms of approximate/approximately. This is a style-and-abbreviation question rather than a universal punctuation law.
Dept/dept. abbreviates department. Cambridge shows periodless and period-ending forms across its dictionary varieties, so the useful rule is to follow the relevant regional or organizational style consistently.
“No.” is a conventional abbreviation for “number” in Chicago-style contexts. The guide keeps it distinct from the number sign and from shortened forms such as num. or n., which may carry other meanings.
