| OP | sandwich without a covering slice of bread |
|---|---|
| OP | heart surgery in which the rib cage is spread open and surgery to fix a heart valve or repair a coronary artery is performed while the heart is stopped and blood is detoured through a heart-lung machine |
| OP | a process for making steel using an open-hearth furnace |
| OP | ready to entertain new ideas |
| OP | (of rooms or buildings) having large rooms with few dividing partitions |
| OP | (computer science) of or relating to or being computer software for which the source code is freely available |
| OP | stork with a grooved bill whose upper and lower parts touch only at the base and tip |
| OP | (of mines and mining) worked from the exposed surface |
| OP | the mining of ore or coal from an open mine |
| OP | (of mines and mining) worked from the exposed surface |
| OP | made open or clear |
| OP | used of mouth or eyes |