treat of
In real, traceable use. Part of the curated seed collection; community review is coming.
Meaning · English
To deal with (a subject).
Register: dated
Where it’s used:
Used
American English
Examples
In the same way, palaeichthyology, or that branch of natural science which treats of fossil fishes, extends our information from the existing fauna back to the earliest advent of vertebrate life upon our globe […]
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “treat of” mean?
To deal with (a subject).
Is “treat of” formal or informal?
treat of is generally dated.