The story
Blend of blood + weave, referencing Astarion being a vampire and Gale a wizard (the Weave is a source of magic in Forgotten Realms lore).
Etymology from Wiktionary, CC BY-SA 4.0.
Bloodweave
Today it means: The ship of characters Astarion Ancunín and Gale Dekarios from the video game Baldur's Gate 3. Full definition →