a blossom or flower: the bloom of a plant, and by extension a flower-shaped ornament in metal or carving
פֶּרַח names what opens on a plant, the blossom or the early bud just breaking out of the stem. It is the noun that belongs to the verb פָּרַח, "to bud" or "to break into bloom," so it can point to the fresh bud that appeared on Aaron's rod or to the wider bloom of a whole landscape, as when the greenery of Lebanon withers.
The same word also names a made thing: the flower-shaped decorations worked into the golden lampstand of the tabernacle, where the cups and knobs and blossoms were shaped like almond flowers, and the flower ornaments cast for Solomon's temple. Here the blossom has become a design, a stylized flower in gold or bronze rather than a living one.
One image ties the two uses together. Whether it grows on a branch or is hammered into metal, a פֶּרַח is the open flower, the point where a plant shows its bloom, and the craftsman simply borrows that shape. A closely related word, צִיץ, covers much the same ground.