Four parts (tessera merē). There were four soldiers, the usual quaternion (tetradion, Act 12:9) besides the centurion (Mar 15:39; Mat 27:54; Luk 23:47). The clothes (himatia, outer clothes) of the criminal were removed before the crucifixion and belonged to the soldiers. Luke (Luk 23:34) mentions the division of the garments, but not the number four. The four pieces would be the head gear, the sandals, the girdle, the tallith (outer garment with fringes).
The coat was without seam (ho chitōn araphos). For chitōn (the inner garment) see Mat 5:40. Araphos is compound of a privative and raptō, to sew together, and so seamless (unsewed together), only here in N.T. It occurs elsewhere in Josephus, Ant. III. 6, 4.
Woven (huphantos). Verbal (old word) from huphainō (some MSS. in Luk 12:27), only here in N.T.