Meanings

1. auxiliaryif; in case; if it is the case that; if it is true thathypothetical form of the copula だ, from なり and sometimes classed as a particle
2. auxiliaryas for; on the topic of
3. conjunctionif that's the case; if so; that being the case
4. conjunctionif possible; if circumstances allow

Examples

• 明日ならどうですか。

  How about for tomorrow?

• 明日天気なら外出します。

  I will go out if it is fine tomorrow.

• 明日雨ならば行きません。

  I would not go if it rains tomorrow.

Sentences from Tatoeba (CC BY 2.0 FR).