Adds «opcode» refs #728

Author: JJ

doc/Language/glossary.pod6

@@ -291,6 +291,10 @@ X<|fiddly>
 
 Too complicated to apply a meta-op to. See L<operator|#Operator>.
 
+=head1 Handle
+
+A handle is a data structure used to store information about some input/output operation such as file or socket reading or writing. Perl 6 uses L<IO::Handle> as a base class for file handles, and L<IO::Socket> for sockets.
+
 =head1 Huffmanize
 
 With reference to L<Huffman coding|https://en.wikipedia.org/wiki/Huffman_coding>,
@@ -719,6 +723,8 @@ Not Yet Implemented
 =head1 opcode
 X<|opcode>
 
+An opcode, or operation code, is a bytecode operation, that is, a command of the language actually used on the virtual machine. They are not usually intended for human consumption, but they are usually specified somewhere, like [this document for MoarVM](https://github.com/MoarVM/MoarVM/blob/27a7befed3c38e2e5dbf7a44f8546dc226b41297/docs/bytecode.markdown).
+
 =head1 Operator
 X<|Operator>