: the 23rd letter of the Greek alphabet see Alphabet Table

psi

2 of 3

noun (2)

: parapsychological psychic phenomena or powers

psi

3 of 3

abbreviation

pounds per square inch

Examples of psi in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
It isn't rated for tire pressures greater than 85 psi (5.9 bar). Ben Coxworth, New Atlas, 3 Nov. 2024 The device is claimed to be +- 0.7% accurate from 0 to 39 psi, and +- 1.4% accurate from 40 to 85 psi, with 0.1 psi precision. Ben Coxworth, New Atlas, 3 Nov. 2024 As with most fat tire bikes, handling is a bit vague, but airing the balloon tires up to near their maximum of 20 psi adds a bit of sharpness and speed while the full suspension keeps the ride plush. William Roberson, Forbes, 28 Oct. 2024 Both have a maximum pumping capacity of 80 psi (5.5 bar) – the Large just gets there faster than the Regular. New Atlas, 24 Oct. 2024 See all Example Sentences for psi 

Word History

Etymology

Noun (1)

Middle English, from Medieval Latin, from Late Greek, from Greek psei

Noun (2)

probably by shortening & alteration from psychic

First Known Use

Noun (1)

15th century, in the meaning defined above

Noun (2)

1942, in the meaning defined above

Time Traveler
The first known use of psi was in the 15th century

Dictionary Entries Near psi

Cite this Entry

“Psi.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/psi. Accessed 26 Nov. 2024.

Kids Definition

psi

noun
ˈsī
: the 23rd letter of the Greek alphabet
Ψ or ψ

Medical Definition

psi

1 of 2 adjective
: relating to, concerned with, or being parapsychological psychic events or powers
psi phenomena

psi

2 of 2 noun
: psi events or phenomena
Last Updated: - Updated example sentences
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