accumulate
Pronunciation: /əˈkjuːmjʊleɪt/
verb

Origin:
late 15th century: from Latin accumulat- 'heaped up', from the verb accumulare, from ad- 'to' + cumulus 'a heap'

Spelling help
Spell accumulate and the related word accumulation with a double c and one m.

two cups and a mug had accumulated in the bowl.