each

In some contexts these two words are nearly interchangeable, as in I examined each puppy in the litter and I examined every puppy in the litter. Here the only difference is a slight shift in perspective from considering the animals individually, with each, to considering them collectively, with every. Either of the words, placed before the noun, requires the noun and the verb to be singular: Each puppy is affectionate.Every puppy is affectionate.Each, though not every, may also be placed after a plural noun, and then the plural governs the verb: The puppies each have their own toys. Each can also refer to two or more, whereas every must refer to three or more. Each can be a determiner (each puppy), a pronoun (each of them), and an adverb (Give them a bowlful each), whereas every is a determiner only (every puppy). The expression each and every relates to a singular noun only, and therefore takes a singular verb only: Each and every passenger is required to present two photo IDs. Avoid use of this expression in formal writing, because it is objected to by some people as unnecessarily wordy.