(telecommunications) A radio that creates and receives radio signals through software controlled DSPs (digital signal processors) with ADCs (analog-to-digital converters) and DACs (digital-to-analog converters).

plural of software defined radio

(psychology) A disputed class of behavioural problems in modern children, ascribed to the fact that they spend little time outdoors.

(chess) An opening characterised by Black responding to 1.e4 with 1...d6 and 2...Nf6, followed by ...g6 and ...Bg7, while allowing White to establish an impressive-looking centre with pawns on d4 and e4.

(British spelling) alternative form of defense mechanism

(British spelling) alternative form of civil defense

Efforts to protect the citizens of a state from military attack.

(finance) A document defining the final terms of an agreement between buyer and seller, typically of a company's assets or stock.

(UK, informal, law) gay panic defense

A chess opening characterized by the moves 1.e4 Nc6, in which the white king's pawn advances two squares and the black queen's knight advances to the bishop file.