tertiary

1. (geology) Something from the Tertiary Period (the former term for the geologic period from 65 million to 2.58 million years ago).Examples: "There is, within our area, a great gap between the Eocene group and the later tertiaries, indicated by the difference of their organic contents. Between the existing fauna of our seas and the oldest stage of the later tertiaries, there is a distinct and extensive relationship of identity of species."

2. (ornithology) A tertiary feather; a tertial.Examples: "The feathers [of the least sandpiper (Calidris minutilla)], black centrally, are margined with bright rufous, especially on the back, scapulars, and tertiaries, and with white tips on the latter; the stripes on the middle of the throat and chest are indistinct or almost absent, more evident on sides of breast."; "Coincident with the dropping out of the fifth or sixth primary is the molt of the outermost tertiary, followed by the adjoining tertiary, and then the third tertiary, which in most passerine birds is the last or innermost."

3. (military) A large stage in some extremely powerful thermonuclear weapons (resembling a greatly-enlarged secondary) which is compressed by the explosion of the secondary until ignition of nuclear fusion takes place, in much the same manner as the secondary is imploded by the primary, and which can allow for the attainment of yields of many tens or even hundreds of megatons, and likely even greater; not used in modern weapons due to a greater focus on the accurate use of sub-megaton weapons, the tremendous size of weapons incorporating a tertiary, and the lack of targets whose destruction would necessitate the use of a three-stage weapon.Examples: "A gigaton-scale weapon would of necessity be a three-stage design (incorporating a fusion tertiary - likely with its own massive fission tamper - in addition to the fission primary and fission-jacketed fusion secondary), as a reasonably-sized primary would likely have difficulty imploding to ignition the enormous secondary that would be required to reach a one-gigaton yield with a two-stage thermonuclear."

4. (Roman Catholicism) A member of a Roman Catholic third order; a layperson who participates in activities similar to those engaged in by men and women who take religious vows (respectively the first and second orders), and who may wear some elements of an order's habit such as a scapular.Examples: "Tertiaries living in places where there is no Church of the Order or of the Third Order can gain all the indulgences they would gain visiting such a church, by visiting their respective parish church, or, where there is no parochial church, by visiting another church or public oratory, and fulfilling the other conditions."; "Immediately after her arrival in Ferrara, while she was still striving to secure the foundation of her exemplary reformed community of Dominican tertiaries, [Lucia] Brocadelli also renewed her attempts to enhance [Girolamo] Savonarola's saintly reputation."

1. (geology) Of or pertaining to the first part of the Cenozoic era when modern flora and mammals appeared.not-comparable

1. (geology) The first part of the Cenozoic era when modern flora and mammals appeared.Examples: "[…] a continental northern Alaskan element, including a series of endemic species and disjuncts that have survived the Pleistocene glaciation in northern Alaska and thus represent relicts of the much warmer Tertiary […]"