null

adjective

• 1 [predic.] having no legal or binding force; invalid:the establishment of a new interim government was declared null and void

• 2having or associated with the value zero.
• Mathematics (of a set or matrix) having no elements, or only zeros as elements.

• 3lacking distinctive qualities; having no positive substance or content:his curiously null life

noun

• 1 literary a zero.

• 2a dummy letter in a cipher.

• 3 Electronics a condition of no signal.
• a direction in which no electromagnetic radiation is detected or emitted.

verb

• combine (a signal) with another in order to create a null; cancel out: the tumour can be more readily identified by nulling the high signal from bone marrow