Also found in: Medical, Encyclopedia, Wikipedia.
Related to rostellum: oncosphere, coracidium


n. pl. ros·tel·la (rŏ-stĕl′ə)
A small beaklike part, such as a projection on the stigma of an orchid or the hooked projection on the head of a tapeworm.

[Latin, diminutive of rōstrum, beak; see rostrum.]

ros·tel′lar adj.
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 -la (-lə)
(Biology) biology a small beaklike process, such as the hooked projection from the top of the head in tapeworms or the outgrowth from the stigma of an orchid
[C18: from Latin: a little beak, from rōstrum a beak]
rosˈtellate, rosˈtellar adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(rɒˈstɛl əm)

n., pl. ros•tel•la (rɒˈstɛl ə)
1. any of various small, beaklike parts, as the mouth tube of sucking bugs or the hook-bearing projection of intestinal tapeworms.
2. a beaklike modified stigma of certain orchids that secretes a sticky fluid, enabling pollen grains to adhere to visiting insects.
[1750–60; < New Latin; Latin: little beak, snout, diminutive of rōstrum snout (see rostrum); for formation, see castle]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
The fruits (1 to 6) are asymmetrical, dorsally rounded, 2.4 to 2.6 mm long by 1.9 to 2.1 mm wide, with pedicel of 0.1 to 0.2 mm or absent, with no rostellum, sometimes with a remnant capitated stigma (Figs.
2A) of 383 [+ or -] 44.21 (291-473) [micro]m of diameter, and a rostellum of 748 [+ or -] 99.93 (652-890) [micro]m of diameter, armed with 2 alternating crowns of 17-19 hooks each, with the larger hooks measuring 313 [+ or -] 64.18 (211-430) [micro]m and the smaller ones 200 [+ or -] 41.29 (124-293) [micro]m (Fig.
An anterior cone shaped rostellum surrounded with two layers of hooks and four rounded suckers were observed (Fig.
Members of the newly proposed genus Versteria have morphologic features that distinguish them from members of the other taeniid genera, such as miniature rostellar hooks, small scolex, rostellum, and suckers; a short strobili; and a small number of testes (1).
Pollinarium 5-5.5 mm long, ca.1.8 mm wide, formed by 2 subclavate, longitudinally cleft, cream-yellow pollinia; viscidium ventral, apical, sheathing the apex of the rostellum, oblong-lanceolate, obtuse, grey, keeled, ca.
The scolex has four suckers and a conical, retractile rostellum "armed" with 1-8 rows of hooks, depending on the age of the parasite.
(2) The majority of orchid flowers attach pollinia indirectly to an adhesive plug (the viscidium) using stalk-like, connective structures produced by the anthers (caudicles) or the rostellum (stipes).