A volume-based keyword tier — sitting between longtail (too low-volume to matter) and main-tail/head terms (too high-volume and broad to be reliably relevant) — flagged as the source of the Amazon Search Query Performance (SQP) Report's "deep insights."
When reviewing the SQP report sorted by brand purchases, the single top term is usually an obvious main-tail term whose story is already known. The actionable, non-obvious funnel problems (see SQP Funnel Stage Diagnostic (Thumbnail vs. Listing Problem)) tend to surface further down the list, in the midtail — terms specific enough to represent a real customer search intent, but with enough volume that fixing them moves meaningful sales.
Apply by deliberately scrolling past the top 1-2 terms in a purchase-sorted SQP export and inspecting the middle of the ranked list, rather than stopping at the head term.