noun:

• that (indicating something distant from both speaker and listener (in space, time or psychologically), or something understood without naming it directly) ➜ 何れ・此れ・其れ
• that person (used to refer to one's equals or inferiors)
• over there - archaism
• down there (i.e. one's genitals) ［あれ］ - colloquialism
• period; menses ［あれ］ - colloquialism

interjection:

• hey (expression of surprise, suspicion, etc.); huh?; eh?

noun:

• that (something mentioned before which is distant psychologically or in terms of time)

interjection:

• tsk tsk; oh-oh; huh; what's that? - expression of mild surprise, incredulity, annoyance, etc.

expression / interjection:

• while surprised; suddenly ➜ あれよあれよという間に【あれよあれよというまに】・あれよあれよという内に【あれよあれよといううちに】