Punctuation matters. It’s the difference between “let’s eat, grandma!” (inviting granny to dinner) and “let’s eat grandma!” (granny is dinner). And so just as we need to be mindful about whether to use its or it’s, we should also be mindful about the little apostrophe that separates lets from let’s.

Lets (no apostrophe) is a conjugated form of the verb “to let.” This means to allow or permit, the opposite of to prevent or forbid.

  • John lets his dog wander the yard freely.
  • I wonder if the teacher will let the kids out early.
  • The airline only lets you have one checked luggage.

It can also be used in the context of renting out a space, like an apartment. This is how we come to the term “sublet,” which is what happens when someone who is renting or leasing space in turn rents or leases that space to someone else.

In math and science, it can also be used to express an assumption, as in “let C equal the speed of light.” This can help to simplify equations for ease of calculation or expression. This type of usage probably won’t come up very often in your typical day-to-day life unless you work with mathematical formulas regularly.

Let’s (with an apostrophe) is a contraction of the words “let us,” serving as a polite imperative. You’re inviting other people to do something or you’re providing an instruction.

  • It’s so crowded here. Let’s eat next door instead.
  • Now that everyone is here, let’s get started.
  • Let’s go to New York for our next vacation!

Both lets (no apostrophe) and let’s (apostrophe) can sometimes be confused for the word lest too. You’ll find that lest comes up most commonly around Remembrance Day in the context of “lest we forget.” It’s a conjunction (a connecting word like “and” or “but”) meaning in an effort to prevent something undesirable.

  • I set three alarms lest I accidentally sleep in.
  • George always dressed drably lest he attract any unwanted attention.
  • Henrietta added a generous tip lest she be seen as cheap.

Are there any other word pairs (or trios) that are separated by a mere apostrophe? Let’s discuss in the comment section below.