oat
Preserved but no longer current.
Meaning · English
An atom. Probable corruption of iota, or perhaps from the small size of an oat. "I never got an OAT of it," I never received the smallest portion.
Era: ca. 1874 (Victorian)
Where it’s used:
Origin
British & Irish English
Sources & notes
Historical definition reproduced from Hotten’s The Slang Dictionary (1874, public domain; Project Gutenberg #42108, retrieved 2026-07-31). Reflects the attitudes of its era.
Common questions
What does “oat” mean?
An atom. Probable corruption of iota, or perhaps from the small size of an oat. "I never got an OAT of it," I never received the smallest portion.
Is “oat” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.