R

Abbreviation or symbol for electrical resistance; radical (usually an alkyl or aryl group, e.g., ROH is an alcohol, RNH₂ an amine); Réaumur; respiration; respiratory exchange ratio; roentgen; the remainder of a chemical formula; the calculated unit representing vascular resistance in the cardiovascular system; arginine; arginyl; purine nucleoside.

Abbreviation or symbol for (in italics) molar gas constant; one of two stereochemical designations in the Cahn, Ingold, and Prelog system; the third product formed in an enzyme-catalyzed reaction.

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Behnken unit; Broadbent registration point; any chemical group [particularly an alfyl group]; a conjugative plasmid responsible for resistance to various elements; electrical resistance; in electrocardiography, the first positive deflection during the QRS complex [wave]; far point [Lat. remotum]; gas constant; organic radical; race; racemic; radioactive; radiology; radius; ramus; Rankine [scale]; rapid accelerator; rate; rate modulation [pacemaker]; ratio; reaction; Reaumur [scale]; receptor; rectal; rectified; red; registered trademark; regression coefficient; regular; regular insulin; regulator [gene]; rejection factor; relapse; relaxation; release [factor]; remission; remote; reperfusion; repressor; residual tumor [TNM (tumor-node-metastasis) classification]; residue; resistance; respiration; respiratory exchange ratio; respiratory quotient; response; responder; rest; restricted; reverse [banding]; rhythm; ribose; Rickettsia; right; Rinne [test]; roentgen; rough [colony]; rub

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R abbr

1) Reaumur

2) rough used in bacteriology

R symbol chemical group and esp. an organic chemical group <thiols have the general formula RSH>

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arginine; organic radical; Rankine (see under scale); rate; expiratory exchange ratio; Rйaumur (see under scale); resistance (def. 3); respiration; rhythm; right; roentgen; rough (colony).