Eighteen is a noun, specifically a cardinal number.
"Eighteenth" is an ordinal number, specifically the ordinal form of the cardinal number "eighteen." In grammar, it can function as an adjective or a noun.
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
"Eighteenth" is an ordinal number, specifically the ordinal form of the cardinal number "eighteen." In grammar, it can function as an adjective or a noun.
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "lecturer" is a noun.
The part of speech for "indefinite" is an adjective.