When you talk about all of one thing, you mean the whole thing. When Shakespeare writes, in As You Like It, “ All the world's a stage,” he means the whole world. You use all to refer to the whole of a particular period of time. George had to cut grass all afternoon. ALL definition: the whole of (used in referring to quantity, extent, or duration). See examples of all used in a sentence. The meaning of ALL is the whole amount, quantity, or extent of. How to use all in a sentence. Synonym Discussion of All. n. The whole of one's fortune, resources, or energy; everything one has: The brave defenders gave their all. the whole of (used in referring to quantity, extent, or duration): all the cake; all the way; all year. the whole number of (used in referring to individuals or particulars, taken collectively): all students. Evidence for the role of the environment is seen in childhood ALL among twins, where only 10–15% of both genetically identical twins get ALL. Since they have the same genes, different environmental exposures explain why one twin gets ALL, and the other does not. All means ‘every one’, ‘the complete number or amount’ or ‘the whole’. We use it most often as a determiner. We can use a countable noun or an uncountable noun after it: … When all refers to a whole class of people or things, we don’t use the: … Who should I meet in New York but Max of all people! = Of all the people in New York, who should I run into but Max! [=I was very surprised to meet Max in New York] So what's the difference? First you need to understand the difference between all and all the. We use all (without an article) when we're talking about the noun in general.