Rare term; the more common word is 戒厳令 (かいげんれい). This form reverses the first two characters.
See also: 戒厳令
厳戒令 is a variant of 戒厳令 and is rarely used.
A rare variant of 戒厳令 (かいげんれい), formed by swapping the first two characters. The exact origin is uncertain, but it may be a historical or idiosyncratic spelling.