WHOLE CHARACTER
卡kǎ, qiǎ
card; a small stiff piece of paper; truck (卡车); calorie (卡路里); cartoon (卡通)
卡 kǎ is a small stiff card: 卡片, 卡车 'truck', 卡通 'cartoon'. As qiǎ it means getting stuck — 卡住, 关卡 'checkpoint'.
ZDIC: 会意,从上、从下 — 'up' pressed onto 'down': caught in between. The two pieces share the middle horizontal stroke (visual aid).
TOP: THE 'UP' PIECE NAMED BY ZDIC
上shàng
up; on top
A standalone character (up; above); characters that use it as a piece state the role on their own pages.
In 卡: top: the 'up' piece named by ZDIC Shown with its documented or clearly limited role.
BOTTOM: THE 'DOWN' PIECE NAMED BY ZDIC
下xià
down; below
A standalone character (down; below); characters that use it as a piece state the role on their own pages.
In 卡: bottom: the 'down' piece named by ZDIC Shown with its documented or clearly limited role.