a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return; "sonar is an acronym for sound navigation ranging"; "asdic is an acronym for antisubmarine detection investigation committee"
igneous rock produced by eruption and solidified on or near the earth's surface; rhyolite or andesite or basalt; "volcanic rock includes the volcanic glass obsidian"
explosively unstable; "a volcanic temper"
relating to or produced by or consisting of volcanoes; "volcanic steam"; "volcanic islands such as Iceland"; "a volcanic cone is a conical mountain or hill built up of material from volcanic eruptions"
having a bearing on or connection with the subject at issue; "the scientist corresponds with colleagues in order to learn about matters relevant to her own research"
the quality of being significant; "do not underestimate the significance of nuclear power"
a meaning that is not expressly stated but can be inferred; "the significance of his remark became clear only later"; "the expectation was spread both by word and by implication"
a subdivision of a written work; usually numbered and titled; "he read a chapter every night before falling asleep"
a series of related events forming an episode; "a chapter of disasters"
a local branch of some fraternity or association; "he joined the Atlanta chapter"
an ecclesiastical assembly of the monks in a monastery or even of the canons of a church
any distinct period in history or in a person's life; "the industrial revolution opened a new chapter in British history"; "the divorce was an ugly chapter in their relationship"
being or involving basic facts or principles; "the fundamental laws of the universe"; "a fundamental incomatibility between them"; "these rudimentary truths"; "underlying principles"
far-reaching and thoroughgoing in effect especially on the nature of something; "the fundamental revolution in human values that has occurred"; "the book underwent fundamental changes"; "committed the fundamental error of confusing spending with extravagance"; "profound social changes"