1785 F. Grose Classical Dict. Vulgar Tongue Tandem, a two wheeled chaise, buggy, or noddy, drawn by two horses, one before the other, that is at length.

1789 Loiterer No. 42. 12 I have not the smallest desire to ride in Mr. Whirligig's Tandem.

1807 Ld. Byron Let. 11 Aug. (1973) I. 131 We shall..proceed in a Tandem..to Inverary.

1821 A. Hodgson Lett. from N. Amer. (1824) II. 110 Painted sleighs..are dashing along [Broadway, New York] in all directions,..some with two horses abreast; some harnessed as tandems, and others with four in hand.

1850 Notes & Queries 1st Ser. I. 382/1 We have a practical pun now naturalized in our language in the word ‘tandem’.

1861 T. Hughes Tom Brown at Oxf. I. i. 4 They drove tandems in all directions, scattering their ample allowances..about roadside inns.

1795 W. Felton Treat. Carriages II. 141 A Tandum..is..two horses in a team, or one before the other to draw a two wheel chaise.

a1805 A. Carlyle Autobiogr. (1860) xii. 449 In the end of summer [of 1764] I went again with Mrs. Carlyle to Harrogate,..I got an open chaise with two horses—one before the other, and the servant on the first.]

a1805 A. Carlyle Autobiogr. (1860) xii. 458 Blackett's horse was very heavy, and my tandem far outran them.

1859 K. Cornwallis Panorama New World I. 104 I..equipped a dog-cart and tandem, for a drive to the diggings.

1885 Pall Mall Gaz. 14 Jan. 3/2 The old political tandem, in which the poor man with talent and the rich man without it pulled together, is no longer possible.

1956 in E. Molloy Automobile Engineer's Ref. Bk. xxx. §7 The Eaton type tandem axle unit has been developed as a method of increasing the proportion of payload to gross vehicle weight.

1969 J. S. Baker & W. R. Stebbings Dict. Highway Traffic 230 Tandem (axles),..an assembly of two axles for the support of the rear of a truck trailer.

1977 ‘D. Rutherford’ Return Load ii. 29 I'd suggest you have one of these new tandem axle Taskvans... They have air-bellow suspension.

1896 G. B. Shaw Let. 5 July (1965) I. 634 I will get a tandem bicycle; and we shall ride along over the celestial plains.

1899 Daily News 11 Jan. 2/4 In the Soudan they used a small dynamo driven by means of a tandem bicycle.

1867 J. Macgregor Thousand Miles in Rob Roy Canoe (ed. 5) ii. 37 In the Canoe Club we have three ‘tandem’ canoes, each for two paddles.

1959 C. M. M. Begg Introd. Genetics x. 137 A tandem duplication can result from unequal crossing over.

1981 L. L. Mays Genetics xii. 529 Tandem duplication of a short region of one chromosome is thought to result from inaccurate crossing over processes.

1967 P. Metzler Advanced Tennis ix. 116 When first confronted with the tandem formation..the left-hander is likely to continue hitting his return in its usual direction.

1976 Tennis Today Oct. 12/1 The American juniors played the whole match using what they call the Tandem Formation, more normally referred to as the Australian Formation in this country.

1968 Globe & Mail (Toronto) 3 Feb. 41/2 (advt.) Executive home. Seven room solid brick bungalow with tandem double garage.

1974 Country Life 7 Mar. (Suppl.) 32 l 2 reception rooms, kitchen/breakfast room. Tandem garage.

1929 Star 21 Aug. 17/1 F. W. Southall is expected to make an attack on the one mile tandem-paced record.

1955 Times 11 July 5/7 D. Marsh (Shaftesbury C.C.) won the 12-hour tandem-paced cycle race at Herne Hill on Saturday.

1895 I. K. Funk et al. Standard Dict. Eng. Lang. II. Tandem-play (Football), a play in which the man running with the ball is preceded or followed, or both preceded and followed, by other men of his own side..to assist him in breaking through the opposing line.

1901 Feilden's Mag IV. 413/1 The fan engines, which were tandem-compound, were afterwards fitted with low-pressure relief-valves, in addition to those fitted in the high-pressure cylinders.

1921 Telegr. & Telephone Jrnl. 7 79/2 With a machine switching tandem exchange large groups..can be established between each local exchange and the tandem exchange.

1923 F. W. Harbord & J. W. Hall Metall. Steel II. xiv. 290 Splitting up the mill into a breaking-down mill, which is placed in front of, and feeds, the smaller finishing mill (the arrangement being usually known as a tandem mill) is preferable where there is a sufficient output to justify employing two sets of men.

1924 W. Aitken Automatic Telephone Syst. III. 79 Tandem working through a tandem office will be introduced into London as quickly as possible.

1933 K. B. Miller Telephone Theory & Pract. III. iv. 243 In large cities..tandem operation is especially useful.

1933 K. B. Miller Telephone Theory & Pract. III. iv. 243 The cost and inconvenience of using the tandem routing must be balanced against the trunk saving which it produces.

1955 Archit. Rev. 117 141/2 A motor assembly known as a Two-speed Tandem Motor combines a squirrel cage and slip-ring motor within a single frame.

1959 Wall St. Jrnl. 3 July 5/5 The New York State Thruway Authority has approved the use of tandem-trailers over its 559-mile highway system. The tandem vehicles—which consist of a heavy duty truck tractor hitched to two regular size trailer units—have been in experimental use.

1967 New Scientist 16 Feb. 397/1 Although the majority of larger telephone exchanges in Britain have direct connections with all other exchanges, many have to route their outgoing calls through central switching exchanges known as tandem exchanges.

1970 Gloss. Aeronaut. & Astronaut. Terms (B.S.I.) vi. 2 Tandem boost, a boost rocket motor assembly which is located at the rear of the missile and co-axially with it.

1971 W. K. V. Gale Iron & Steel Industry: Dict. Terms 54 Continuous mill (tandem mill), any rolling mill in which the stands are arranged in tandem.

1976 NBR Market-place (Wellington, N.Z.) iii. 3/4 Tandem blades clog up with shaving foam and don't give as even a shave as the single blade.

1978 Detroit Free Press 14 Apr. 16 d/2 Carrying 22 extra bolts and a new coupling device, a tandem tanker rumbled down a test track.