sa·phe·nous vein 
(sə-fēnəs)
(sə-fēnəs)n.
Either of two main superficial veins of the leg, one larger than the other, that begin at the foot.
[saphenous, pertaining to the saphena, a saphenous vein, from Middle English, from Medieval Latin saphēna, saphenous vein, from Arabic ṣāfin, standing with one leg slightly raised, saphena, participle of ṣafana, to stand with one leg slightly raised.]