time dilation

noun

: a slowing of time in accordance with the theory of relativity that occurs in a system in motion relative to an outside observer and that becomes apparent especially as the speed of the system approaches that of light

called also time dilatation

Examples of time dilation in a Sentence

Recent Examples on the Web

Today’s topic was time dilation. —Bennett Durando, Denver Post, 18 Apr. 2026

This effect, called time dilation, would be especially pronounced for the Hail Mary, which is moving at more than 90 percent of the speed of light. —Encyclopedia Britannica, 23 Mar. 2026

Weiss: Speaking of Rocky, what went into creating this entirely new species that evolved to the point of inventing interstellar travel without ever learning about radiation or time dilation? —Josh Weiss, Forbes.com, 20 Mar. 2026

This time dilation gives the Doctor the chance to spend 17 years (or just over a week, depending on your point of view) giving SAM a childhood. —Richard Edwards, Space.com, 26 Feb. 2026

Word History

First Known Use

1923, in the meaning defined above

Rhymes for time dilation

• abbreviation
• abomination
• acceleration
• accentuation
• accommodation
• accreditation
• acculturation
• accumulation
• acetylation
• adjudication
• administration
• adulteration