code point
A value in the Unicode codespace.
code unit
The minimal bit combination that can represent a unit of encoded text for processing or interchange. The Unicode Standard uses 8-bit code units in the UTF-8 encoding form, 16-bit code units in the UTF-16 encoding form, and 32-bit code units in the UTF-32 encoding form.
A range of numerical values available for encoding characters. For the Unicode Standard, this is the range of integers from 0 to 10FFFF16.
encoding form
Mapping that determines how each code point for a Unicode character is to be expressed as a sequence of one or more code units.