What part of speech is circularise?

Circularise can be categorized as a verb.

Parts of speech

1. circularise is a verb, present, 1st person singular of circularise (infinitive).
2. circularise is a verb (infinitive).

Verb
circularise - cause to become widely known; "spread information"; "circulate a rumor"; "broadcast the news"
circularise - distribute circulars to
circularise - canvass by distributing letters