adverb, noun which may take the genitive case particle 'no'
to that extent; so much; that much
Expresses a high degree or extent, often with a nuance of surprise or emphasis. Used adverbially or adjectivally with の.
Even though I warned him so much, he forgot again.
Even though I practiced that much, I lost the match.
With that much talent, he will probably succeed.
I've never seen scenery that beautiful.
This is the first time I've seen damage that severe.
あれほど points to a degree tied to something distant from both speaker and listener, while それほど points to a degree tied to something near the listener or already mentioned.
あれほど refers to a degree associated with something distant from the speaker, while これほど refers to a degree associated with something close to the speaker.
Kanji form using 程; seen in some written contexts.
Rare kanji form using 彼; may be confused with other readings.
Compound of あれ (that, distal demonstrative) and ほど (extent, degree).