Abeam: At a relative bearing of 90 degrees (abeam to starboard) or 270 degrees (abeam to port).
Aboard: on or inside a ship
Actual: In military speak, “Actual” means the actual officer in charge. For example, “Eucharis Actual” would be ShôshôKetsurui Hanako, commander of the YSS Eucharis. If you call the gunship Eucharis, you might be talking to a communications officer on the Eucharis, but if you call Eucharis Actual, that means you only want the actual captain of the Eucharis. The purpose is to differentiate between an officer and their radioman who is handling their traffic.
Adrift: not under power or control
Aft: to the rear of the ship
Abaft: further aft
After: furthest aft
Ahoy: A greeting to get attention. Originally a Viking battle-cry.
Aitsu あいつ: “this f–ker”
“All things cost blood:” The motto of the First Fleet. It means nothing can be created or accomplished without sacrifice, and probably violence.
Are あれ: that. Can also be used like “huh?!” when surprised.
ASAP: As soon as possible
Asoko あそこ: there.
Astern: Directly behind a ship
Athwart: At right angles to
Avast: Stop that!
AWOL: Absent without leave; unexcused absence. Warning: desertion can be punished by death.
Aye: Yes (understood)
Aye aye: (understood; I will comply); WILCO
Baba ばば: Old lady/hag
Baka ばか: Idiot!
Balls: Any time that starts with 00 (e.g. “Balls Thirty”)
Barrette: Internal turret cylinder armor
Battle Rattle: Body armor and gear (“Everyone suit up in full battle rattle!”)