相(あい)まってCombined with, Coupled with, Together with

相(あい)まって is a structure used for showing that (A) and (B) are things that will perform some sort of synergistic task in order to achieve the result of (C). In many cases, either (A) or (B) alone could achieve (C), but their combined action will bring about a better result. This structure is a combination of 相(あい), 'mutual', or 'reciprocal', and the て-form of the う-Verb 俟(ま)つ 'to wait on'.

In this pattern, both (A) and (B) will often come before 相(あい)まって, with either of the case-marking particles と or が being used after the nouns. Common translations include '(A) combined with (B) will (C)', or 'coupled together with (A), (B) will (C)'. As for a literal translation, 'mutually depending on each other, (C)' is fairly close to the exact nuance. See the fun-fact for more about this.

Fun Fact

Although 俟(ま)つ 'to wait on' and 待(ま)つ 'to wait for' are very similar, they have a primary difference in their focus. 待(ま)つ indicates waiting in the sense of 'waiting for (A) to come', while 俟(ま)つ indicates 'waiting for (A) to go'. What this means is that with 相(あい)まって and other uses of 俟(ま)つ, the important thing happens after (A) and (B) come together. This gives the nuance of (A) and (B) having some kind of reliance on each other in order to do (C). Due to 俟(ま)つ being far less common in modern Japanese, it will often be written in hiragana.