a

1. 1 —used as a function word before singular nouns when the referent is unspecified a man overboard and before number collectives and some numbers a dozen

2. 2 :  the same birds of a feather swords all of a length

3. 3a —used as a function word before a singular noun followed by a restrictive modifier a man who was here yesterdayb :  any a man who is sick can't workc —used as a function word before a mass noun to denote a particular type or instance a bronze made in ancient timesd —used as a function word before a proper noun representing an example or type the attractions of a Boston or a Clevelande —used as a function word before a proper noun to indicate limited knowledge about the referent a Mr. Smith called to inquire about the jobf —used as a function word before a proper noun to distinguish the condition of the referent from a usual, former, or hypothetical condition a triumphant Ms. Jones greeted her supporters

4. 4 —used as a function word with nouns to form adverbial phrases of quantity, amount, or degree felt a bit tired

1. 1 chiefly dialectal :  on, in, at

2. 2 :  in, to, or for each twice a week

archaic

1. :  have I might a had husbands afore now — John Bunyan

1. :  of —often attached to the preceding word kinda lotta

1. 1 ace

2. 2 adenine

3. 3 ampere

1. argon

1. 1 :  on :  in :  at abed

2. 2 :  in (such) a state or condition afire

3. 3 :  in (such) a manner aloud

4. 4 :  in the act or process of gone a-hunting atingle

1. :  not :  without asexual —a- before consonants other than h and sometimes even before h, an- before vowels and usually before h achromatic ahistorical anastigmatic anhydrous

1. :  replacing carbon especially in a ring aza-

1. :  oxide silica

1. angstrom unit

1. 1 :  the first letter of the English alphabet

2. 2 :  a grade that shows a student's work is excellent

3. 3 :  a musical note referred to by the letter A

1. 1 :  someone or something being mentioned for the first time There's a dog in the yard.

2. 2 :  the same two of a kind

3. 3 :  ¹any 1 It's hard for a person to understand.

4. 4 :  for or from each an apple a day The new theater charges ten dollars a person.

5. 5 :  ²one 3 a dozen doughnuts a week This is a third the size of that. Hint: A is used before words that do not begin with a vowel sound.

1. 1 :  on :  in :  at abed

2. 2 :  in (such) a state, condition, or manner afire aloud

3. 3 :  in the act or process of gone a-hunting

1. :  the one of the four ABO blood groups characterized by the presence of antigens designated by the letter A and by the presence of antibodies against the antigens present in the B blood group

1. 1adenine

2. 2ampere