Definition:Time/Unit/Hour

Definition

The hour is a derived unit of time.

Conversion Factors

\(\ds \)

\(\)

\(\ds 1\)

hour

\(\ds \)

\(=\)

\(\ds 60\)

minutes

\(\ds \)

\(=\)

\(\ds 60 \times 60\)

\(\ds = 3600\)

seconds

Symbol

$\mathrm {hr}$

The symbol for the hour is $\mathrm {hr}$.

The $\LaTeX$ code for \(\mathrm {hr}\) is \mathrm {hr} .

Historical Note

The hour was formerly defined as being $\dfrac 1 {24}$ of a mean solar day.

Sources

• 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $1.$ Units and Abbreviations: $1.3$ British and other units
• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $60$
• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $3600$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $60$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $3600$
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): hour
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): hour