1844 Punch 22 June 261/1 The party that claim To take to themselves of Young England the name;..It seems after all are the tribe of Old Clo!

1851 A. O. Hall Manhattaner 6 Groups of old clo' shops, gaudily set forth with parti-colored handkerchiefs.

1874 L. Troubridge Life amongst Troubridges (1966) 95 Any nice clo' make one feel a different person.

1922 J. Joyce Ulysses ii. xiv. [Oxen of the Sun] 403 Where the Henry Nevil's sawbones and old clo?

1932 Daily Express 28 Jan. 15/3 Cornhill…here were a corn market and small shops inhabited by haberdashers and old clo' men.

1981 P. Van Greenaway ‘Cassandra’ Bell xiii. 161 The cry of an old clo' man gave reassurance that God was, after all, in his heaven.

1941 A. P. Gagge et al. in Science 7 Nov. 429/1 The unit for thermal insulation of clothing is logically the amount of insulation necessary to maintain in comfort..a sitting-resting subject in a normally ventilated room (air movement 20 ft/min or 10 cm/sec) at a temperature of 70°F (21°C) and a humidity of the air which is less than 50 per cent. This unit of insulation may be called 1 clo.

1951 Canad. Mining Jrnl. Aug. 65/3 It was not until the Second World War that..a new unit called the ‘clo’ was coined in order to express..the efficiency of a textile in retaining warmth.

1977 R. F. Goldman in Hollies & Goldman Clothing Comfort i. 7 Proposed by Dr. Gagge and his colleagues..some 30 years ago, one clo was characterized as the intrinsic insulation..of the typical business suit worn in those days.

1980 New Scientist 14 Aug. 537 Wool fibre, several centimetres thick, down and the new 3M material have clo values of 0.9, 1 and 1.8 respectively.

1986 H. G. Jerrard & D. B. McNeill Dict. Sci. Units (ed. 5) 29 A clo is defined in physical terms as the amount of insulation that will allow the passage of 1 calorie m⁻² h⁻¹ with a temperature gradient of 0.18°C between the two surfaces.