horizontal combination vs horizontal integration

horizontal combination and horizontal integration both are nouns.

Word	Noun	Adjective	Verb	Adverb
horizontal combination	Yes	No	No	No
horizontal integration	Yes	No	No	No

As nouns, horizontal combination and horizontal integration are synonyms defined as:

horizontal combination and horizontal integration: absorption into a single firm of several firms involved in the same level of production and sharing resources at that level

horizontal combination (noun)	horizontal integration (noun)
absorption into a single firm of several firms involved in the same level of production and sharing resources at that level	absorption into a single firm of several firms involved in the same level of production and sharing resources at that level