What is the definition of "Al-Mutaba' and Al-Shahid"?

A mutabi' (corroborating narration) is when a narrator relates a hadith in which another narrator shares in the narration from his same shaykh. If their shaykh is the same and their hadith is the same, it is called a complete mutaba'ah (perfect corroboration). However, if he narrates the hadith from his shaykh's shaykh, it is called an incomplete mutaba'ah (imperfect corroboration). As for a shahid (supporting narration), it is when the hadith comes with its exact wording or its meaning through the path of another Companion. The condition for a shahid is the difference in the Companion, whereas the condition for a mutabi' is that the Companion must be the same.