1874 Proc. Royal Geogr. Soc. 18 157 This [earthen fort] is crowned with an obo or cairn, covered with the usual ragged streamers of silk and cotton tied to sticks, an emblem of the superstitious regard which the Mongols..have for the place.

1913 D. Carruthers Unknown Mongolia i. 245 Obos are built at places where special attention is to be drawn to the sacredness of the spot; we have seen these shrines in every part of the Yenisei Basin and on North-west Mongolia.

1923 G. Collins Valley of Eyes Unseen 58 The obo consists of slabs of slate..inscribed all over with Tibetan characters.

1934 H. Haslund Tents in Mongolia vi. 59 The two obo were..erected at the point where the caravan route crosses the boundary between Inner and Outer Mongolia.

1958 F. Schutze tr. H. Stëbel Mewu Fantzu 33 Every mountain on which there stands an obo..is particularly sacred. The obo of the nomadic Mewu Fantzu consists of a wooden structure into which sacrificial wooden arrows are stuck annually.

1978 P. Matthiessen Snow Leopard iv. 272 The strange rows of upright slabs, like gravestones, known as obo, which are characteristic of northern Tibet and Mongolia.