also: かけかえ
replacement; substitute; rebuilding; changing
Refers to something that can replace or be substituted for another, often used in the phrase かけがえのない (irreplaceable).
She is an irreplaceable presence in my life.
Family is an irreplaceable presence.
この経験はかけがえのないものになった。
This experience became something irreplaceable.
Family is an irreplaceable treasure.
代替 is a formal, often technical term for substitution (e.g. 代替品), whereas 掛け替え is used almost exclusively in the emotional expression 掛け替えのない.
Usually written in kana; the kanji spellings 掛け替え and 掛け変え are less common.
Kanji spelling using 替 (replace); restricted to reading かけがえ.
Alternate kana spelling reflecting the reading かけかえ; rarely used.
Alternate kanji spelling using 変 (change); reading かけかえ is less common.
Compound of 掛け (kake, continuative form of 掛ける 'to hang, set') + 替え (kae, continuative form of 替える 'to replace'). The exact historical derivation is uncertain, but the meaning of 'replacement' is conventionally associated with these components.