Yes, but the term "byte" doesn't tell you much. Most people assume that a byte is 8-bits which isn't true. If the definition the of `char` was `1 octet`, then you could make safer assumptions about "What's the result of `' ' * 13`?".

From ISO/IEC 9899:2011:

  3.6

  byte

  addressable unit of data storage large enough to hold any
  member of the basic character set of the execution
  environment

  NOTE 1 It is possible to express the address of each
  individual byte of an object uniquely.

  NOTE 2 A byte is composed of a contiguous sequence of bits,
  the number of which is implementation-defined. The least 
  significant bit is called the low-order bit; the most
  significant bit is called the high-order bit.

Edit: Reading further into the C11 spec, `5.2.4.2.1 Sizes of integer types <limits.h>`, it says that `CHAR_BIT` must be 8 bits (or larger). A google search suggests there exists some processors that have 16-bit bytes and others that have 32-bit bytes.