21 C.F.R. § 801.15
(a) A word, statement, or other information required by or under authority of the act to appear on the label may lack that prominence and conspicuousness required by section 502(c) of the act by reason, among other reasons, of:
(b) No exemption depending on insufficiency of label space, as prescribed in regulations promulgated under section 502(b) of the act, shall apply if such insufficiency is caused by:
(c)
(1)
(i) All words, statements, and other information required by or under authority of the act to appear on the label or labeling for a device shall appear thereon in one or more of the following formats:
(D) A symbol not accompanied by adjacent explanatory text that:
(1) Is contained in a standard that FDA recognizes under its authority in section 514(c) of the act;
(2) Is used according to the specifications for use of the symbol set forth in FDA's section 514(c) recognition; and
(3) Is explained in a paper or electronic symbols glossary that is included in the labeling for the device and the labeling on or within the package containing the device bears a prominent and conspicuous statement identifying the location of the symbols glossary that is written in English or, in the case of articles distributed solely in Puerto Rico or in a Territory where the predominant language is one other than English, the predominant language may be used;
(E) A symbol not accompanied by adjacent explanatory text that:
(1) Is established in a standard developed by a standards development organization (SDO);
(2) Is not contained in a standard that is recognized by FDA under its authority in section 514(c) of the act or is contained in a standard that is recognized by FDA but is not used according to the specifications for use of the symbol set forth in FDA's section 514(c) recognition;
(3) Is determined by the manufacturer to be likely to be read and understood by the ordinary individual under customary conditions of purchase and use in compliance with section 502(c) of the act;
(4) Is used according to the specifications for use of the symbol set forth in the SDO-developed standard; and
(5) Is explained in a paper or electronic symbols glossary that is included in the labeling for the device and the labeling on or within the package containing the device bears a prominent and conspicuous statement identifying the location of the symbols glossary that is written in English or, in the case of articles distributed solely in Puerto Rico or in a Territory where the predominant language is one other than English, the predominant language may be used;
(iii) For purposes of paragraph (c)(1)(i) of this section:
(B) The term “symbols glossary” means a compiled listing of:
(1) Each SDO-established symbol used in the labeling for the device;
(2) The title and designation number of the SDO-developed standard containing the symbol;
(3) The title of the symbol and its reference number, if any, in the standard; and
(4) The meaning or explanatory text for the symbol as provided in the FDA recognition or, if FDA has not recognized the standard or portion of the standard in which the symbol is located or the symbol is not used according to the specifications for use of the symbol set forth in FDA's section 514(c) recognition, the explanatory text as provided in the standard.
[41 FR 6896, Feb. 13, 1976, as amended at 81 FR 38930, June 15, 2016]