having no legal or binding force; invalid

the court ruled that the contract contained several infringements and therefore declared it null and void

having or associated with the value zero

lacking distinctive qualities; having no positive substance or content

his curiously null life

a zero

a dummy letter in a cipher

a condition of no signal

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