(mathematics) the symbol ∓, meaning "minus or plus", used alongside the plus-minus sign to show that a negative value is to be taken where the positive value is indicated by the plus-minus sign, and vice versa (as in (x ± 1) / (x ∓ 2), which means (x + 1) / (x - 2) and (x - 1) / (x + 2)).

(intransitive, idiomatic) To formalize an agreement.

(military) Any call sign which represents two or more facilities, commands, authorities, or units. The collective call sign for any of these includes the commander thereof and all subordinate commanders therein.

(military) A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these.

(military) A call sign that represents all stations within a net.

(military) A call sign that identifies a tactical command or tactical communication facility.

(military) A call sign assigned in accordance with the provisions of the International Telecommunications Union to identify a radio station. The nationality of the radio station is identified by the first or the first two characters. (When used in visual signaling, international call signs are referred to as “signal letters.”)

The shaka, a gesture made with a fist with the thumb and little finger extended

A dactylological sign language used in seven different countries, based on Old French Sign Language. ISO 639-3 code: fsl.

A language that uses hands, facial expressions, and other bodily behavior to communicate both concrete and abstract ideas; some signs are based on English words, but BSL syntax and grammar are not based on English.