growing together; developing together
Refers to two or more things (often plants, but also abstract concepts) growing or developing in tandem. Somewhat literary or poetic.
The pine and plum trees in this garden have a relationship of growing together.
Their friendship deepened as if growing together.
Kana spelling; may be used when the kanji are considered difficult or obscure.
Compound of 相 (ai, 'mutual') and 生い (oi, 'growth'). The exact historical derivation is uncertain, but the word is conventionally associated with the idea of things growing together.