1.04 Plurals

Add an s, but not an apostrophe, to form the plural of most abbreviations:

• ADMs
• BMWs
• CAs
• CRs
• FTEs
• GICs
• MPs
• PCBs
• 747s

Use an apostrophe and s to form the plural of numerical names of aircraft ending in a single letter:

• 727-100C’s
• 747B’s
• Cessna 402B’s

In cases where the resulting form would be ambiguous, add an apostrophe before the s:

• c.o.d.’s
• Q’s and A’s
• SIN’s

Add an apostrophe and s to form the plural of abbreviations containing more than one period, and an s without an apostrophe, to form the plural of abbreviations with only one period. In the latter case, the s precedes the period:

• G.M.’s
• Gens.
• pts.

The plurals of Mr. and Mrs. are irregular:

• Mr.
  • Messrs.
• Mrs.
  • Mmes.

The plural forms of the abbreviations for certain bibliographic references are different:

• l. (line)
  • ll. (lines)
• p. (page)
  • pp. (pages)
• f. (and the one following)
  • ff. (and those following)
• c., ch. (chapter)
  • c., ch. (chapters)
• MS (manuscript)
  • MSS (manuscripts)
• s. (section)
  • ss. (sections)
• subs. (subsection)
  • subss. (subsections)

Note that SI/metric symbols maintain the same form for both singular and plural and are written without periods, except at the end of a sentence:

• 1 cm
• 5 cm, centimetres
• 75 kg, kilograms
• The boxer weighed only 75 kg, kilograms.

© Public Works and Government Services Canada, 2013
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