also: アリのとう
noun
Refers to the mound or structure built by ants. The term is straightforward and used in everyday contexts.
庭に蟻の塔ができていた。
An anthill had formed in the garden.
蟻塚 also means anthill but is less common and may carry a slightly more literary or formal tone.
Compound of 蟻 (ari, 'ant') + の (no, possessive particle) + 塔 (tō, 'tower'), literally 'ant tower'. The reading ありのとう is the standard kun'yomi-based reading.