A.T. Robertson Commentary Mark 14:3

"And while he was in Bethany in the house of Simon the leper, as he sat at meat, there came a woman having an alabaster cruse of ointment of pure nard very costly; [and] she brake the cruse, and poured it over his head." — Mark 14:3 (ASV)

As he sat at meat (κατακειμενου αυτου). Matthew 26:7 uses ανακειμενου, both words meaning reclining (leaning down or up or back) and in the genitive absolute. See on Mt 26:6 in proof that this is a different incident from that recorded in Lu 7:36-50. See on Mt 26:6-13 for discussion of details.

Spikenard (ναρδου πιστικης). This use of πιστικος with ναρδος occurs only here and in Joh 12:3. The adjective is common enough in the older Greek and appears in the papyri also in the sense of genuine, unadulterated, and that is probably the idea here. The word spikenard is from the Vulgate nardi spicati, probably from the Old Latin nardi pistici.

Brake (συντριψουσα). Only in Mark. She probably broke the narrow neck of the vase holding the ointment.