大口徑

large caliber

see 大夫[dai4 fu5]

big; large; great / older (than another person) / eldest (as in 大姐[da4 jie3]) / greatly; freely; fully / (dialect) father / (dialect) uncle (father's brother)

big mouthful (of food, drink, smoke etc) / open mouth / gulping / gobbling / gaping

mouth / classifier for things with mouths (people, domestic animals, cannons, wells etc) / classifier for bites or mouthfuls

caliber / diameter of opening

footpath / track / diameter / straight / directly