What does the prefix sub- mean?
Sub- comes from the Latin sub, which means "under" or "below". It shows a lower physical position or a lower level in a hierarchy. The central idea is always "below", in a physical sense or in importance.
ESEN
Prefix · below / inferior level
sub-
Signals position below or a lower level: subway, submarine, subtitle, subconscious.
Basic
Written by Bryan López, English teacher · Updated
Sub- also means "less than enough"
Sub- can show a level below the standard: something that does not reach what is expected, or something that happens below the level of consciousness. In that use, it no longer talks about a position in space, but about a quality or a level. To know which one it is, ask yourself whether the word describes a place or a measure of quality.
How it is used
Attaches to nouns and adjectives with no spelling change:
- sub- + noun (position)way → subwaymarine → submarinetitle → subtitlefloor → subfloor
- sub- + adjective (lower level)standard → substandardoptimal → suboptimalconscious → subconscioustropical → subtropical
Pronunciation: /sʌb/, with a short "u" as in "cup".
How it is pronounced
sub-/sʌb/
Tap the button to hear how the prefix sounds. Each word in the table has its own audio.
Examples
Root word
With sub-
In a phrase
- waysubwayTaking the subway is the fastest way across the city.
- marinesubmarineThe crew spent three months on a submarine in the Atlantic.
- titlesubtitleThe film had no subtitles, so the dialogue was hard to follow.
- conscioussubconsciousMany of our daily decisions are driven by subconscious habits.
- standardsubstandardThe building failed inspection because the materials were substandard.
- tropicalsubtropicalThe coastal region has a subtropical climate with hot, humid summers.
- urbansuburbanMany families moved to suburban areas during the pandemic.
Common mistakes
suburb = same as downtown or city center
suburb = a residential area on the outskirts of a city
"The suburbs" are the outer residential areas, away from the center. They are the opposite of "downtown." In American English, the suburb-vs-city distinction carries strong cultural meaning.
subway means the metro everywhere in English
subway = metro in American English; in British English it is "the Underground" or "the Tube"
In Britain, "subway" can refer to a pedestrian underpass. The London metro is called "the Underground" or colloquially "the Tube."
A trick to remember it
Sub- is easy to spot: subway, submarine, subtitle, subconscious, subtropical. Every time you see sub- at the start of a word, think "below" or "one level under."
Practise what you learned
Exercise 1 · Form the word
Exercise 2 · Pick the right one
"The quality of the materials in that building was completely ___ and failed every inspection."
Exercise 3 · Pick the right one
What is the difference between "subway" in American and British English?
Frequently asked questions
What does the prefix sub- mean in English?
The prefix sub- signals position below or a lower level: subway, submarine, subtitle, subconscious.
How do you pronounce sub-?
The prefix sub- is pronounced /sʌb/. For example, "subway".
Can you give an example of a word with sub-?
"way" becomes "subway". It is a typical example of the sub- prefix.
Other useful prefixes
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