semaphore
/ˈsɛməfɔr/
verb
- To send a message using a semaphore system, especially with flags or arms.
- He learned to semaphore the alphabet during his training.
- We semaphored our position to the rescue team across the valley.
- The sailors semaphored a warning to the nearby boat.
noun
- A system of sending messages using two flags held in different positions to represent letters or numbers.
- The scout learned how to send a message using semaphore.
- Sailors used semaphore to communicate between ships before radio became common.
- At summer camp, we practiced spelling our names with semaphore flags.
- A signal or device that gives a visual warning or instruction, such as a railway signal with moving arms.
- Old railway stations still have semaphore signals that raise and lower their arms.
- The train stopped because the semaphore showed a red light.
- The driver watched the semaphore carefully to know when it was safe to proceed.
- In computing, a variable used to control access to a shared resource by multiple processes or threads.
- The programmer used a semaphore to prevent two processes from writing to the same file at once.
- Without a semaphore, the shared data could become corrupted by simultaneous updates.
- A semaphore helps manage traffic between different parts of a computer program.