What is Subscribe?

Legal Definition
In the law of contracts. To write under; to write the name under; to write the name at the bottom or end of a writing. Wild Cat Branch v. Bali, 45 Ind; 213; Davis v. Shields, 26 Wend. (N. Y.) 341.
-- Black's Law Dictionary
Legal Definition
To sign beneath.
-- Ballentine's Law Dictionary