single fileˌsingle ˈfile noun 
Examples
We walked in single file across the bridge.—single file adverb
ExamplesEXAMPLES FROM THE CORPUS
Thesaurus- A narrow spiral staircase leads up from chamber 2b to 2c; characters must ascend in single file.
- Ambush patrols at night were always in single file, with no point or flank security.
- Men passed us, dark, bearded, stern, armed with sticks, walking swiftly in single file.
- Okay single file, we're coming to a wood.
- Teams of horses in single file hauled trains of a dozen flat-topped wagons loaded with granite along these rails.
- The jungle area we had to go into was so thick, the APCs could only travel single file.
- The stairs are approached along a raised pavement so narrow the people must have walked along it in single file.
- Then we are instructed to leave Damrosch Park single file.
Longman Language Activatora line of people► line
Phrases a line of people who are standing behind each other or next to each other: · The Queen is walking slowly along the lines of soldiers, occasionally stopping to ask a question.in a line (=forming a line): · The photographer asked us to stand in a line.form a line (=make a line): · The teacher got the children to form a line before they went into the hall.
► row a line of people who have been arranged to stand or sit next to each other, especially when there are several lines of people arranged one behind another: · Can you see me in the photo? I'm in the back row on the left.in a row: · The hotel staff stood in a row to greet their important guests.
► queue British /line American a number of people who are standing one behind another, waiting to do something: · There was a queue of about fifteen people at the bus stop.queue for: · The line for the movie went right around the block.form a queue/line (=make a queue/line): · The women who were waiting outside the toilets began to form a queue.in the queue (=part of the queue): · Excuse me, are you in the queue?
► in single file if a group of people walk in single file , they walk one behind another in a line: · The path was so narrow that we had to walk in single file.
► procession a group of people or vehicles that move slowly along in a line, especially as part of a public ceremony: · We were held up by a long funeral procession.· The children were eager to take part in the carnival procession.
► parade an event in which a line of people such as musicians, dancers etc, or a line of decorated vehicles, go down the street while other people watch them in order to celebrate something: · A lot of soldiers were missing from the Victory parade.· When Johnson arrived home after the championships a big parade was held in his honour.
► column a long moving line of people, especially soldiers: · The column of French soldiers passed us on their way to the battlefront.· Columns of men and women were making their way towards the central square.
PHRASES FROM THE ENTRY► in single file
in single file moving in a line, with one person behind another: - The class walked in single file down the hall.
- The path was so narrow that we had to walk in single file.
We walked in single file across the bridge.—single file adverb