It can be an adverb, as in 'things were cheaper then'. It can also be an adjective as in being at the time indicated 'the then Governor'. It can be used as a noun as 'we have not been back since then' or 'till then, goodbye'.
'then' can be used as an adverb when put into a sentence that means at some specified time in the past or future. Also as an adjective as in the sentence 'existing at that time'
what part of speech is work
adverb
i want to know what part of speech is camping
what part of speech is beneath
what part of speech is eleven
The part of speech for "answer" is a noun.
part of speech
The part of speech for this particular word is a noun.
what part of speech is beneath
what part of speech is work
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech of "came" is a verb.
The part of speech for "buried" is a verb.
The part of speech for "rapid" is an adjective.
The part of speech for "lecturer" is a noun.