The a-series demonstrative pronoun: something distant from both speaker and listener, or something both understand without naming directly.
あれは何ですか。
What is that?
昨日のあれ、もう終わった？
Did you finish that thing from yesterday?
Used for a person, typically an equal or inferior; it can sound blunt or overly familiar if used for someone who deserves respect.
あれは昔から頑固なやつだ。
That guy has been stubborn since way back.
Temporal use referring back to a known time or event, especially in expressions such as あれから, 'since then.'
あれから十年たった。
Ten years have passed since then.
that place; that one over there
Can stand for a distant or indicated place when the place is understood from context; あそこ is the more explicit locative word for 'over there.'
今夜泊まる町は、向こうに見えるあれです。
The town where we will stay tonight is that one you can see over there.
down there; one's genitals
Colloquial euphemism for the genitals, often written アレ to emphasize vagueness or embarrassment.
その男性は「アレが痛い」とぼかして言った。
The man vaguely said, 'It hurts down there.'
Colloquial euphemism for menstruation, often written アレ and used when the speaker does not want to say it directly.
今日はアレだから、プールは休む。
I'm on my period today, so I'll skip swimming.
Rare attested kanji spelling for あれ. It is easily confused with the common word 彼 read かれ, so learners should normally write あれ.