What is the meaning of けむ?

, : smoke

used to make the past conjectural form of verbs

  1. presents a supposition about a past event
  2. presents a supposition about the cause of a past event
  3. presents hearsay about a past event

presents a supposition about a past event

presents a supposition about the cause of a past event

presents hearsay about a past event

Source: wiktionary.org