directional

1. ADJ If something such as a radio antenna, microphone, or loudspeaker is directional, it works most effectively in one direction, rather than equally in all directions at once. (广播天线、麦克风或扬声器)定向型的[技术]

Unless he was equipped with a directional microphone, he was out of earshot. 除非给他配备一个定向扬声器，否则谁也听不见他。

2. ADJ Directional means relating to the direction in which something is pointing or going. 方向的[技术] [usu ADJ n]

Jets of compressed air gave the aircraft lateral and directional stability. 压缩气体喷流从侧面和正面稳定了机身。