underlying

Etymology

adj

1. lying underneath
   We dug down to the underlying rock.
   During the track renewals, advantage was taken to redrain the area and the old spent ballast was removed down to the underlying rock, new ballast and drains being provided throughout. 1950 January, “Re-Signalling at Liverpool Lime Street Station”, in Railway Magazine, page 43
   Sometimes, the underlying layers are exposed by erosion, revealing the story of the rocks like an open book. 2012, Chinle Miller, In Mesozoic Lands: The Mesozoic Geology of Arches and Canyonlands National Parks, Kindle edition
2. basic or fundamental
   Points and straight lines are underlying elements of geometry.
   The underlying problem with transport policy is that there no coherent strategy. Ministers have tended to encourage greater use of motor vehicles through both transport and (particularly) planning policies, while simultaneously warning of the terrible consequences of unfettered growth of road use. December 2 2020, Christian Wolmar, “Wales offers us a glimpse of an integrated transport policy”, in Rail, page 56
3. implicit
   Many nursery rhymes have an underlying meaning.

noun

1. (finance) The entity from whose performance a derivative derives its value.

verb

1. present participle and gerund of underlie