log Definition

log¹
noun

1a. Part of a tree trunk or branch that has been cut, especially for firewood;
1b. A tree trunk or large branch that has fallen to the ground.
2. A detailed record of events occurring during the voyage of a ship or aircraft, etc.

Thesaurus: record, diary, journal, account, chart, daybook, tally.
3. A logbook.
4. A float, originally made of wood, attached by a line to a ship and used for measuring its speed.

verb logged, logging

1a. To record (distances covered on a journey, events, etc) in a book or logbook;
1b. To record (speed) over a set distance.
2. To cut (trees or branches) into logs.
intr
3. To cut logs.

Idiom: sleep like a log

To sleep very soundly.

Etymology: 14c.

Phrasal Verb: log in or on

To start a session on a computer system, usually one shared by several users and requiring a password to be entered;To make a connection with another computer over a network.

Phrasal Verb: log out or off

To end a session on a computer system by keying in a closing command (noun 7);To close a connection with another computer which has been accessed over a network.

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log² logarithm

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logarithm
noun

1. The power to which a real number, called the base (sense 9), must be raised in order to give another number or variable, eg the logarithm of 100 to the base 10 is 2 (written log10 100 = 2).

Derivative: logarithmic
adj

Derivative: logarithmically
adverb

Also called Napierian logarithm. See also antilogarithm.

Etymology: 1614: first coined by John Napier (1550‐1617), Scottish mathematician, from Greek logos word or ratio + arithmos number.