(fandom slang) Initialism of Pokémon X and Y.

(biology) The system that determines the sex of humans, most other mammals, some insects (Drosophila), and some plants (Ginkgo), in which females have two of the same kind of sex cell (XX) and males have two distinct sex cells (XY).

plural of XY problem

A communication problem where a person seeking help (for example, from a computing helpdesk) provides misleadingly incomplete information about the source of the problem and thus receives inaccurate or unhelpful suggestions about how to fix it.

Alternative form of XY system

(botany) A vascular tissue in land plants primarily responsible for the distribution of water and minerals taken up by the roots; also the primary component of wood.

(chemistry) Any of a group of three isomeric aromatic hydrocarbons, found in coal and wood tar.

(dated) xylyl

Of or relating to wood and especially xylem

plural of xylene