Of, or related to signals.

plural of signall

(US, telephony) An audible signal to the calling party that indicates failure to complete the requested connection; an engaged tone

An unclear message, often contradicting a situation.

An American crayfish, Pacifastacus leniusculus, having a large claw that it waves to attract a mate.

Alternative spelling of smoke signal

(often pluralized) A method of long-distance communication sometimes used in ancient and undeveloped societies, consisting of messages conveyed by means of columns or intermittent puffs of smoke.

Alternative form of time signal

A building, typically adjacent to or spanning a railway line, from where signals, points and (sometimes) level crossings are controlled. / The alarm-box of a police or fire-alarm system.

plural of signal box