alternative means; alternative method
A formal or technical term for a substitute way of doing something, often used in problem-solving or planning contexts.
To solve this problem, we must consider alternative means.
Secure an alternative method in case transportation stops.
代案 is a more general 'alternative plan/proposal', while 代替手段 specifically refers to a concrete method or means.
代替案 is an 'alternative plan', often more abstract; 代替手段 emphasizes the practical means or procedure.
Compound of 代替 (だいたい, 'substitution') and 手段 (しゅだん, 'means'). The word follows standard Sino-Japanese compounding patterns.