null

Concise Oxford English Dictionary © 2008 Oxford University Press:
null/nʌl/

▶adjective

• 1 (usu. in phr. null and void) having no legal force; invalid.

• 2 having or associated with the value zero.

  ■ Mathematics (of a set or matrix) having no elements, or only zeros as elements.

• 3 having no positive substance.

▶noun

• 1 a dummy letter in a cipher.

• 2 Electronics a condition in which no signal is generated; something generating no signal.

▶verb Electronics cancel out, creating a null.

– origin ME: from Fr. nul, nulle, from L. nullus ‘none’, from ne ‘not’ + ullus ‘any’.