Part of speech is a noun. Phonetic symbol:
[English] [? kw? z? n]
[Korean] [? kw? z? n]
Example 1: He devoted himself to acquiring knowledge.
He takes time to acquire knowledge.
Example 2: His second hydrophilicity is the natural order of acquiring hydrophilicity.
His second hypothesis is the natural order in acquisition theory.
As can be seen from two example sentences, the word acquisition is generally used after the adverb the.