The meaning of a word in the sentence determines to what part of speech it belongs.
The same word may be sometimes one part of speech, sometimes another.
Words of entirely separate origin, meaning and use sometimes look and sound alike such as in…
The minstrel sang a plaintive lay.
He lay on the ground.
But the following examples show that the same word may have more than one kind of grammatical office (or function). It is the meaning which we give to a word in the sentence that determines its classification as a part of speech.
Adverbs and Prepositions
The same word can be used as adverb as well as preposition.
Adverb : Jill came tumbling after.
Preposition : He returned after the accident.
Adverb : We went below.
Preposition : Below us lay the valley.
Adverb : The weeds sprang up.
Preposition : We walked up the hill.
Other examples are aboard, before, beyond, down, inside, underneath.
Miscellaneous examples of variation are the following.
Noun : The calm lasted for three days.
Adjective : Calm words show quiet minds.
Verb : Calm your angry friend.
Other examples are iron, stone, paper, sugar, salt, bark, quiet, black, light, head, wet, round, square, winter, spring.
Noun….Wrong seldom prospers.
Adjective….You have taken the wrong road.
Adverb….Edward often spells words wrong.
Verb….You wrong me by your suspicions.
Noun….The outside of the castle is gloomy.
Adjective….We have an outside stateroom.
Adverb….The messenger is waiting outside.
Preposition….I shall ride outside the coach.
Adjective…..That boat is a sloop.
Pronoun…..That is my uncle.
Conjunction….You said that you would help me.
Adjective…..Neither road leads to Utica.
Pronoun…..Neither of us arrived in time.
Conjunction…..Neither Tom nor I was late.
Preposition…..I am waiting for the train.
Conjunction…..You have plenty of time, for the train is late.
Interjection…..Hurrah! The battle is won.
Noun….I heard a loud hurrah.
Verb….The enemy flees. Our men hurrah.