Definição e Significado de "a"

um, uma

used when we want to talk about a person or thing for the first time or when other people may not know who or what they are

Example

She found a job at a company downtown.

She bought a new book yesterday.

There is a movie theater in the mall.

1.1

um, uma

used before a noun when we are not talking about a specific person or thing

Example

She brought a gift for the birthday party.

She received a letter from a friend.

um, uma

used to show someone or something belongs to a group or type

Example

The lion is a wild animal.

The rose is a flower with beautiful petals.

He is a student in the university.

SUBSTANTIVO

A, um

the musical pitch A, which is a specific note in the diatonic scale commonly used in Western music

What is "A"?

In music, the pitch "A" is a specific note that is used as a reference point for tuning and playing. It is one of the twelve notes in the musical scale and is represented by the letter "A". Each "A" note can be higher or lower in pitch depending on the octave. For example, "A4" is a common reference pitch that vibrates at 440 Hertz and is often used to tune musical instruments. This note helps musicians keep their music in tune and create harmonious sounds.

um angstrom, uma unidade de medida angstrom

a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation

grupo sanguíneo A, o grupo sanguíneo A

the blood group whose red cells carry the A antigen

the 1st letter of the Roman alphabet

um nucleotídeo, uma unidade de nucleotídeo

one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)

adenina

(biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA

Exemplo