Your instinct that there may be a distinction is not incorrect. Words invariably carry a connotation with them, and a good drafter will choose their words to take advantage of the connotations in order to help the parties and the courts understand the parties intentions. For example, to me "revocation" carries with it a connotation that it is a unilateral action that one party to an agreement can take to cease contractual obligations where that party has granted something, whereas "termination" carries the connotation that it is some outside condition that is causing the cessation.
For example, if I wanted to express the idea that a painter can paint buildings on campus as much as they would like (and get paid for it), but the payer can cancel this arrangement, I would probably use "revoke." "Corporation agrees that painter may elect to devote time to re-painting any buildings on campus designated by corporation as in need of painting, and corporation shall pay painter $100 per hour for time spent painting; provided that Corporation may revoke this agreement at any time in its sole discretion by notice to painter, and following revocation, painter shall have no further rights to payment hereunder."
Contrariwise, if I wanted to express the idea that painter's obligations are subject to a force majeure clause, I would probably use "termination." "In exchange for $100 per hour, painter agrees to paint the buildings on campus designated by corporation; provided that in the event of fire, flood, riot, epidemic or other act of God affecting the campus, this agreement shall be terminated and the parties shall have no further rights or obligations hereunder."
Revocation and termination essentially mean the same things here: cancellation of contractual obligations. However, one term or the other provides a different connotation that is appropriate in different contexts.
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In matters of law, there are complexities, nuance and exceptions to everything, including things said above. Don't expect a complete discussion in a forum post. Moreover, even if there are no complexities, nuance and exceptions that apply to your situation, there may be consequences that apply to you that you should consider. The fact that I don't know what complexities, nuance, exceptions and consequences apply to your specific situation is one reason (among many) that the things said above are not legal advice. So, I'll say what you hear so many lawyers say. The above is not legal advice. I am not your lawyer. You can rely on my legal advice only when we have discussed your specific situation after entering into an engagement letter with me or my law firm, and have agreed to pay me or my law firm for the provision of legal advice.