1.adjectiveAlongside or abreast; opposite the center of the side of the ship or aircraft.
"The island was directly abeam of us."
2.adverbOn the beam; at a right angle to the centerline or keel of a vessel or aircraft; being at a bearing approximately 090 Degrees or 270 Degrees relative.
3.adverbAlongside or abreast; opposite the center of the side of the ship or aircraft.