The first letter of the English alphabet.

英文的第一个字母。

A speech counterpart of orthographic a.

a 字的发音。

One arbitrarily designated a., esp. as the first in order or class.

以 a 为带称的人或物；尤指居首者。

Sixth tone in the scale of C major, or the scale having this tone as the keynote.

【乐】A 音；A 调。

Superior grade rating, as of bonds, credit risks, or student's work.

【美】优等；甲等。

Blood type.

【医】（血液）A 型。

Something shaped like an A.

A 字型之物。

a is used before a word beginning with a consonant sound.

在发子音为首的单字前用 a。

Used before unspecified countable nouns.

用在非特定可数名词之前。

Any.

凡是；任何。

One.

一个。

The same.

同一。

Per.

每。

One like another.

像...的一个(人或物)。

Used before an uncountable noun (abstract, material, proper) to refer to a countable meaning of noun.

用在不可数名词（抽象、物质、专有）前，使该名词作为可数名词的用法。

Used before the first one of a pair of nouns that seems to be a single whole.

二个名词若成为一组时，用于最初的名词前。