What is the meaning of 1?

The cardinal number one, a single thing or unit.

A digit in decimal and every other base numbering system, including binary, octal, and hexadecimal.

The identity element with respect to multiplication in a ring.

Bit state corresponding to binary digit 1, or on or true.

A Boolean or truth value corresponding to true.

The one-point topological space, trivial ring, trivial group, a category with a single object or a (canonical) singleton.

indicator function of a set.

the pitch of a tone, either high or low depending on local convention; '1' is most commonly the highest or lowest pitch (but see 0)

tone number 1, typically identified with dark level yin ping (陰平). May simply be level ping tone () if the yinyang distinction is not made.

accent 1 in Norwegian, Swedish and Limburgish.

Deliberate misspelling of !, imitating someone who is too excited to consistently press the shift key while typing exclamation marks.

Abbreviation of one-shot or one-shotted.

Clipping of 180. (180° spin)

one

top

Abbreviation of ein.

The number one (1).

Deliberate misspelling of !

-et (singular indefinite nominative; the)

-et (neuter singular)

Source: wiktionary.org