open out

present singular third person opens out · participle present opening out · participle past opened out · past opened out

1. To expand, to widen, to unwrap, unfold or uncover, to spread out from a compact state.

   To obtain the required overhead clearance at Stockport, it will be necessary to open out the Edgeley tunnels.

   1958 July 28, “Bridge Reconstruction for L.M.R. Electrification”, in Railway Magazine, page 488

   1 more example

   Once though the station the deep-throated exhaust of G.C.R. engines, and particularly the "Directors", could be heard in ascending crescendo as the drivers opened out to take the gradient.

   1954 July, C. R. L. Coles, “Memories of the Great Central”, in Railway Magazine, page 464

2. To facilitate wider access or expand options.

   The plan will open out the region for trade.

3. To increase the amount of air in an engine, such as by pressing on the accelerator to open a throttle plate or butterfly valve.