1. To pledge or contribute (a sum of money).
2.
a. To sign (one's name) at the end of a document, especially to attest to or authenticate it.
b. To sign one's name to (a document) in attestation, testimony, or consent: subscribe a will.
3. To authorize (someone) to receive or access electronic texts or services, especially over the Internet.
4. To purchase or claim the shares of (a new issue of stock, bonds, or other securities): a bond offering that is fully subscribed.