celery
芪 is a rare kanji for celery, a specific plant. Its meaning is narrow and concrete, with no clear abstract extensions.
芪 combines the plant radical 艹 with 氏, which likely provides a phonetic cue. The exact historical development is uncertain.
The grass radical 艹 sits above 氏, like celery stalks growing from the ground. Think of 氏 as the base of the plant, with the leafy celery on top.
For キ, imagine a key-shaped celery stalk: key -> キ, and the celery unlocks a fresh flavor.