their

[ thair; unstressed ther ]

pronoun

1. a form of the possessive case of plural they used as an attributive adjective, before a noun:

   their home;

   their rights as citizens;

   their departure for Rome.

2. a form of the possessive case of singular they used as an attributive adjective, before a noun:
   1. (used to refer to a generic or unspecified person previously mentioned, about to be mentioned, or present in the immediate context): A parent should read to their child.

      Someone left their book on the table.

      A parent should read to their child.

   2. (used to refer to a specific or known person previously mentioned, about to be mentioned, or present in the immediate context):

      I’m glad my teacher last year had high expectations for their students.

   3. (used to refer to a nonbinary or gender-nonconforming person previously mentioned, about to be mentioned, or present in the immediate context):

      My cousin Sam is bad at math, but their other grades are good.

their

/ ðɛə /

determiner

1. of, belonging to, or associated in some way with them

   their own clothes

   she tried to combat their mocking her

   their finest hour

2. belonging to or associated in some way with people in general not including the speaker or people addressed

   in many countries they wash their clothes in the river

3. belonging to or associated in some way with an indefinite antecedent such as one, whoever, or anybody

   everyone should bring their own lunch

Usage

See they

Grammar Note

See he ¹, me, they.

Word History and Origins

Origin of their¹

First recorded in 1150–1200; Middle English their(e), ther(e), from Old Norse theirra “their”; replacing Old English thāra, thǣra; they

Word History and Origins

Origin of their¹

C12: from Old Norse theira (genitive plural); see they , them

Example Sentences

LRAs are a critical component of HIV cure research due to their role in what is called "kick and kill," the idea that HIV can be reawakened and actively targeted to eliminate the viral reservoir.

From Science Daily

By isolating compounds from dried powder from the plant's bark, Drs. Tietjen, Ntie-Kang, and their teams were able to run assays designed to test whether the compounds reversed HIV latency in vitro -- a hypothesis that was confirmed for four out of six isolated compounds.

From Science Daily

Thousands of scientists and plant breeders have since used that genome in their own research on the genetic makeup underlying various characteristics, such as seed protein and oil content, plant architecture and productivity, and disease resistance and abiotic stress tolerance in soybeans.

From Science Daily

In their recent paper, the Ma lab identified transcription initiation sites for about 40,000 genes in soy.

From Science Daily

Soybeans have experienced two whole-genome duplication events throughout their history, both several millions of years ago.

From Science Daily

Their Vs. There Vs. They're

What’s the difference between their, there, and they're?

Their is the possessive form of the personal pronoun they, essentially meaning belonging to or possessed by them, as in Is that their car, or ours? There is commonly used to introduce sentences or to indicate where something is, as in It’s over there, next to the window. They’re is a contraction of they are.

There are many instances in which they’re confused because their pronunciations are exactly the same. (See what we did there?)

There are easy ways to remember which spelling is right, and they’re actually built into each word.

You can remember that their is the one that’s used to show possession (like his and her) by remembering that it includes the word heir (a person who inherits possessions).

When it’s used to indicate location, there functions a lot like here (even though it can mean the opposite), and the word here is right inside of it.

The apostrophe in they’re indicates that it’s a combination of two words and signals that it’s the one you want to use when you mean they are.

Here’s an example of their, there, and they’re used correctly in the same sentence.

Example: It’s hard to work as a team in that environment—when they’re in there, they’re their own worst enemies.

Want to learn more? Read the full breakdown of the difference between their, there, and they’re.

Quiz yourself on their vs. there vs. they're!

In what order should their, there, and they’re be used in the following sentence?

_____ shoes are over _____, right next to where _____ sitting.

A. their, there, they’re
B. there, they’re, their
C. they’re, their, there
D. their, they’re, there