a, m., older form ríðari or ríðeri, 645. 110, Fms. x. 88, Geisli (in the burden), where it rhymes to striðum; and so in the oldest vellums, Eluc., Greg., Pd.: [Germ. ritter and reiter; Dan. ridder and rytter]:—a rider, horseman, but esp. a knight: the word, like most of those formed with inflexive -ari, is of foreign origin; for the old Northmen or Scandinavians make no reference to horsemen in battle till the 12th or 13th century, Fms. vii. 56, 236, xi. 331, cp. vi. 411 (referring to the English in the battle of Stanford-bridge), Stj. passim; Guðs riðari, Geisli; riddara nafnbót, Bær. 6; riddara-búnaðr, -skjöldr, -vápn, -höfðingi, Fms. v. 148, vi. 225, Stj. 163, 204, Bær. 5; riddara-meistari, Stj. 513; riddara-kappi, Str.:—a knight in chess, Ó. H. 167, Sturl. iii. 123.

COMPDS: riddaradómr, riddaraherr, riddaraíþrótt, riddaraliga, riddarasaga, riddaraskapr, riddarasveinn, riddaratign.