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n. pl. pri·mor·di·a (-dē-ə)
An organ or a part in its most rudimentary form or stage of development.

[Latin prīmōrdium; see primordial.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


n, pl -dia (-dɪə)
(Biology) biology an organ or part in the earliest stage of development
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(praɪˈmɔr di əm)

n., pl. -di•a (-di ə)
the first recognizable, histologically differentiated stage in the development of an organ.
[1665–75; < Latin prīmōrdium, in pl.: beginnings, elementary stage =prīm(us) first (see prime) + ōrd(īrī) to begin + -ium -ium1; compare exordium]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.primordium - an organ in its earliest stage of development; the foundation for subsequent development
organ - a fully differentiated structural and functional unit in an animal that is specialized for some particular function
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
The mandible is the first pharyngeal arch which is formed from primordium through migrating the neural crest cells which appear in the duration of the fourth week of gestation.
The latissimus dorsi muscle derives genetically from the same primordium muscle as the teres major, which originates as muscular band of cranial-caudal orientation found between the eleventh rib and the adjacent vertebra, and extending to the humerus, the latter being its primitive point of insertion (Orts Llorca, 1970; Haninec et al.).
The embryo in most monocots-including Cyperaceae-bears a prominent primary root primordium (or radicle), with an often clearly visible root cap (Figs.
At the root of the artery, the valvar primordium was initially observed and was contiguous with the OFT cushion [Figure 5]c.
With regards to the viscerocranium components which shares in formation of different structures of the sound transmitting apparatus; the ventral component of the mandibular arch (Meckel's cartilage primordium; M.C.PR) and the dorsal component of the mandibular arch (pterygoquadrate; P.Q) appears as mesenchmatous structures (Figure 2).
Should you bear witness to primordium protruding from a mycelial mat, you will want to shout from the rooftops.
A distinctive feature of this stage is the 90[degrees] angle between the lateral protocerebrum and the eye growth zone, from which the optic stalk primordium will form in later stages.
Initially, "adaxial" and "abaxial" genes are expressed throughout the leaf primordium, and, as the leaf develops, their expression becomes restricted to their respective domains due to the mutually exclusive actions of their protein products [90].
This is slowly divided into a ventral and dorsal part of the foregut, becoming the respiratory primordium and the upper gastrointestinal tract, respectively [10].
TFCs are derived from the thyroid primordium, or thyroid anlage, that originates from a thickening of the endodermal epithelium in the foregut at the base of the prospective tongue.
Anatomical sections of control and vehicle control mice fetuses showed normal left and right ventricles of brain, serous glands, intra-retinal space, lens, neural layer of retina, mandibular gland and cerebral aqua duct, hyaloid cavity, nasal septum and nasal cavity, primordium of frontal bone, follicle of vibrissae (Fig.