custom--customs: (1) habits, ways; (2) revenue duties.
letter--letters: (1) the alphabet, or epistles; (2) literature.
number--numbers: (1) figures; (2) poetry, as in the lines,--
I lisped in _numbers_, for the numbers came.--POPE.
Tell me not, in mournful _numbers_.--LONGFELLOW.
_Numbers_ also means issues, or copies, of a periodical.
pain--pains: (1) suffering; (2) care, trouble,
part--parts: (1) divisions; (2) abilities, faculties.
[Sidenote: _Two classes of compound words._]
50. Compound words may be divided into two classes:--
(1) _Those whose parts are so closely joined as to constitute one word._ These make the last part plural.
courtyard dormouse Englishman fellow-servant fisherman Frenchman forget-me-not goosequill handful mouthful cupful maidservant pianoforte stepson spoonful titmouse
(2) _Those groups in which the first part is the principal one, followed by a word or phrase making a modifier._ The chief member adds _-s_ in the plural.
aid-de-camp attorney at law billet-doux commander in chief court-martial cousin-german father-in-law knight-errant hanger-on
NOTE.--Some words ending in _-man_ are not compounds of the English word _man_, but add _-s_; such as _talisman_, _firman_, _Brahman_, _German_, _Norman_, _Mussulman_, _Ottoman_.
51. Some groups pluralize both parts of the group; as _man singer_, _manservant_, _woman servant_, _woman singer_.
[Sidenote: _Two methods in use for names with titles._]
52. As to plurals of names with titles, there is some disagreement among English writers. The title may be plural, as _the Messrs. Allen_, _the Drs. Brown_, _the Misses Rich_; or the name may be pluralized.
The former is perhaps more common in present-day use, though the latter is often found; for example,--
Then came Mr. and Mrs. Briggs, and then _the three Miss Spinneys_, then Silas Peckham.--DR. HOLMES.
Our immortal Fielding was of the younger branch of the _Earls of Denbigh_, who drew their origin from the _Counts of Hapsburgh_.--GIBBON.
The _Miss Flamboroughs_ were reckoned the best dancers in the parish.--GOLDSMITH.
The _Misses Nettengall's_ young ladies come to the Cathedral too.--DICKENS.
The _Messrs. Harper_ have done the more than generous thing by Mr. Du Maurier.--_The Critic_.