当且仅当

Traditional form:

當且僅當

Pinyin (reading):

dāngqiějǐndāng

Definitions:

• if and only if

Characters:

• 当 - appropriate, timely; to act, to serve; the sound of bells
• 且 - moreover, also (post-subject); about to, will soon (pre-verb)
• 仅 - only, merely, solely, just
• 当 - appropriate, timely; to act, to serve; the sound of bells

Traditional characters:

• 當 - appropriate, timely; to act, to serve; the sound of bells
• 且 - moreover, also (post-subject); about to, will soon (pre-verb)
• 僅 - only, merely, solely, just
• 當 - appropriate, timely; to act, to serve; the sound of bells