pushing jackn. a form of jack (Jackn.2 11) used to move a heavy object a short distance.
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1868 Sci. Amer. 25 Jan. 61/1Pushing jack for railroad car.
2003 Geogr. Jrnl.169 13/1 Once the building was safely on the tracks, six hydraulic pushing jacks were placed in the excavated ground to the south. These were then used to push the lighthouse along the tracks.