Yours, Etc.: Origins and Uses of 8 Sign-Offs
from first and third person singular of Old English durran "to brave danger, dare; venture, presume," from Proto-Germanic *ders- (cf. Old Norse dearr, Old High German giturran, Gothic gadaursan), from PIE *dhers- "to dare, be courageous" (cf. Sanskrit dadharsha "to be bold;" Old Persian darš- "to dare;" Greek thrasys "bold;" Old Church Slavonic druzate "to be bold, dare;" Lithuanian dristi "to dare," drasus "courageous").
An Old English irregular preterite-present verb: darr, dearst, dear were first, second and third person singular present indicative; mostly regularized 16c., though past tense dorste survived as durst, but is now dying, persisting mainly in northern English dialect. Meaning "to challenge or defy (someone)" is first recorded 1570s.
1590s, from dare (v.).
Differential Analyzer REplacement. A family of simulation languages for continuous systems.
["Digital Continuous System Simulation", G.A. Korn et al, P-H 1978].