Entry 2 senses · 2 variants Webster, 1913 Sith /sēth/ · IPA /siːθ/ prep., adv., & conj. n. 01 prep., adv., & conj. Since; afterwards; seeing that. 1. Since; afterwards; seeing that.[Obs.] “We need not fear them, sith Christ is with us.” — Latimer. “Sith thou art rightful judge.” — Chaucer. 02 n. Time. 1. Time.[Obs.] “And humbly thanked him a thousand sithes.” — Spenser.