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What does sub mean?

When we come across the word “sub”, we often think about words that begin with this prefix, such as ‘submarine’ or ‘subway’. However, sub is not just limited to these words. ‘Sub’ has a variety of meanings and uses in English, and it can have different implications based on the context in which it is used.

In this blog post, we will explore the various meanings and uses of sub, how it differs from other prefixes, common examples of its use, and related words.

Prefix Sub

As a prefix, ‘sub’ means “under,” “below,” “inferior,” or “less than,” and it is often used to indicate that something is secondary or subordinate to something else. For instance, “subfloor” means ‘the floor beneath’ the main floor, while “subordinate” means a person who is lower in rank or position.

Some common examples of words that beginning with “sub” include:

  • Subway – an underground railway system for urban commuters
  • Submarine – a vessel that can travel underwater
  • Subzero – a temperature below zero degrees Celsius or Fahrenheit
  • Subroutine – a sequence of instructions that can be called multiple times
  • Subtitle – a translated text below the main text in a movie or TV show
  • Subcompact – a small car with less interior space than a compact car

Sub vs. Other Prefixes

Sub is often confused with other prefixes, such as “under,” “below,” and “less,” as these words also mean “inferior” or “less than.” However, there is a subtle difference between them.

For example, “under” refers to something that is physically below or beneath another object. In contrast, “sub” refers to something that is not foremost or inferior. Similarly, “less” is a root word that means “to a smaller extent,” while ‘sub’ relates to something that is subordinate to, in any sense, a superior. Meanwhile, “below” indicates an object’s position relative to something else, while “sub” indicates a quality of being subordinated.

Sub as a Noun or Verb

In addition to being a prefix, “sub” can also function as a verb or noun. For instance, as a verb, “sub” means to substitute someone or something for another person or object. Examples include a teacher’s substitute or a sports player being substituted during a game.

As a noun, “sub” refers to a submarine sandwich, one of the most popular types of sandwiches found in the United States. These sandwiches have a variety of fillings and are usually made with Italian bread.

Related Prefixes and Words

Sub is not the only prefix that means “under” or “less than.” Other related prefixes include:

  • “hyp” meaning “under” or “less than”, eg. hypodermic
  • “infra” meaning “under” or “beneath”, eg. infrastructure
  • “infra” meaning “beneath” but not inferior, eg. infrared
  • “subter” meaning “beneath” or “secret”, eg. subterfuge

Other words related to ‘sub’ include “subpar,” “subjugate,” and “subscribe,” which also have meanings associated with being secondary or inferior.


In conclusion, “sub” is a versatile prefix in English used to indicate something that is secondary, subordinate, or inferior, and it can be used in a variety of ways, including as a prefix, verb, or noun. While it is often confused with other similar prefixes such as “under,” “below,” and “less,” there are subtle differences in the meanings of these words. Regardless, understanding how to use “sub” and similar prefixes will help you communicate more effectively in written and spoken English.


What does it mean to sub someone?

Subbing someone means to substitute or replace someone temporarily in a particular role or position. This term is commonly used in different contexts, such as in sports, education, or work. In sports, for example, if a player is unable to participate in a game or needs to take a break, a substitute player may be called to take their place on the field. Similarly, in the workplace, someone might be asked to sub or cover for a colleague who is absent for some reason.

In education, subbing typically refers to teaching. Teachers or tutors are sometimes unavailable due to planned absences or unexpected emergencies. Therefore, a substitute teacher is called to fill in the gap temporarily. Substitute teachers may follow prepared lesson plans or create their own depending on the situation. This ensures that students don’t miss out on valuable learning opportunities and the overall learning experience is not disrupted.

In the entertainment industry, subbing or standing by is common practice, especially in theaters. This is when an understudy or an alternate performer is ready to take over a role in case the lead performer cannot continue for any reason.

Subbing someone or substituting means replacing or filling in for someone who is temporarily unavailable. It is a crucial aspect of teamwork, education, and different industries that ensures the smooth functioning of different operations.