«إجماع الصحابة بنص البعض وسكوت الباقين، ويقال له: الإجماع السكوتي»
Some Companions expressly state the ruling while the others remain silent; this is called tacit consensus.
The first category involves explicit assent from all, whereas the second involves explicit expression from some and silence from the rest. Silence is thus intrinsic to its definition.
This does not imply that any unexplained silence in ordinary life creates ijma‘. The legal claim still depends on establishing the relevant circumstances of the expressed view and the remaining jurists’ silence.