This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
綶 combines 糸 (thread) with 果 (fruit/result), but the exact historical development and original meaning are uncertain.
With 糸 (thread) and 果 (fruit), imagine tying fruit together with thread, but since the meaning is unclear, treat this as a visual placeholder.
For カ, picture a car (カ) made of thread and fruit: a fragile car that barely holds together.