Terminology for secret sharing?
I believe there is strong enough precedence for using the term threshold decryption for the second. 

The abstract of this paper states:


  A threshold decryption scheme is a multi-party public key cryptosystem that allows any sufficiently large subset of participants to decrypt a ciphertext, but disallows the decryption otherwise.


Sounds to me like what you are talking about. A search for "threshold decryption" turns up plenty of hits too.