What does the measure word 一片 mean? and how to use it?
About 一片, there are some explanations:


Refers to flat and thin (eg: 一片肉)
Refer to the ground surface (eg: 一片空地)
Refer to flaky patches (eg: “黄河远上白云间，一片孤城万仞山。”---王之涣 《凉州词》)
Refer to diffuse scattered (eg: 一片红光)
Refer to gather together (eg: 响声连成一片)
Refer to mood, the mind (eg: 一片心意)
Refer to language (eg: 自做一片文字)
Refer to the whole piece (eg: 军民打成一片)


Hope that can help.