Webster's 1828 Dictionary
ISCHIADIC
a.[L. ischiadicus, from ischias, the sciatica, from ischium, the hip. ] Pertaining to the hip. The ischiadic passion or disease is ranked by Cullen with rheumatism. It is a rheumatic affection of the hip joint. It is called also sciatica. It is sometimes seated in the tendinous expansion which covers the muscles of the thigh, but its most common seat is in the muscles, or in the capsular ligament, and it is then either rheumatic or gouty.
Webster's 1913 Dictionary
ISCHIADIC
Is `chi *ad "ic, a. Etym: [L. ischiadicus, Gr. Sciatic. ] (Anat. )
Defn: Ischial. [R.] Ischiadic passion or disease (Med. ), a rheumatic or neuralgic affection of some part about the hip joint; -- called also sciatica.