How many letters does the top answer for “the act of enclosing something in a case” have?

The most common answer is encasement (10 letters).

Crossword clue: the act of enclosing something in a case

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

encasement 10 letters wn-def

the act of enclosing something in a case

incasement 10 letters wn-def

the act of enclosing something in a case

the act of enclosing something inside something else 50% similar → envelopment, inclosure