A node is a discrete member of a network which interacts with other nodes to form the network. Bitcoin nodes store and validate the blockchain and exchange blocks and transactions with one another in order to maintain consensus.
A non-custodial solution, also known as a self-custodial solution, describes any method of storing bitcoin which does not give a third party access to a user’s private keys.
A nonce is a meaningless number which miners include in each block in order to change the hash of their block. The nonce is continuously changed until a valid hash or Proof-of-Work is found.