Pavilions (亭) are iconic in Chinese gardens and parks - open-sided structures with elegant roofs, designed for rest, poetry, and enjoying scenery. Famous examples include 醉翁亭 (the Old Drunkard's Pavilion).
亠 is the indexing radical - a horizontal stroke with a dot above, the abstract lid or roof-cap shape. It crowns many architectural and high-place chars (京, 高, 亮) and here gives the pavilion its peaked tip.
口 here is not a mouth but a small enclosed space - the body of the pavilion seen from above, or the open cavity beneath the roof. It contributes the idea of an open, walkable structure rather than a sealed building.
冖 is the cover radical - a flat lid stretched horizontally. In 亭 it forms the second tier of roof, repeating the lid motif and reinforcing the layered, eaved silhouette of a Chinese garden pavilion.
丁 provides the sound, shifted to tíng. The same phonetic gives 停 (stop), 厅 (hall) and 钉 (nail) - the t-/d- pavilion-and-hall family clusters around this pillar shape.
