Entry 3 senses · 2 variants Webster, 1913 Seepage /sēp'-ĭj/ · Seep·age · IPA /sˈiːpɪdʒ/ n. n. 01 n. Water that seeped or oozed through a porous soil. 1. Water that seeped or oozed through a porous soil.[Scot. & U. S.] 02 n. The act or process of seeping; percolation. 1. The act or process of seeping; percolation. 2. a fluid that seeps out of a container; as, seepage from a reservoir.