一旦

Traditional form:

一旦

Pinyin (reading):

yīdàn

Definitions:

• in case (sth happens)
• if
• once (sth happens, then...)
• when
• in a short time
• in one day

Characters:

• 一 - one; a, an; alone
• 旦 - dawn; morning; day

Traditional characters:

• 一 - one; a, an; alone
• 旦 - dawn; morning; day