Petal or sepal, where there is no distinct difference between the two. terminal:

The petals and the sepals collectively. See: Illustration

These modified leaves are present in flowers that have no clear distinction between sepals and petals.

 Petal or sepal, where there is no distinct difference between the two.

a free segment of a perianth that is not differentiated into a calyx and corolla.

[Perianth] -- One of the segments (when not fused) of the perianth; used when the perianth is not differentiated into calyx (with sepals) and corolla

(n) an undifferentiated part of a perianth that cannot be distinguished as a sepal or a petal (as in lilies and tulips)

A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of th [..]

When the sepals and petals of a flower are indistinguishable, they are referred to as tepals. Tepals are common in many groups of monocots. More info?

One of the modified leaves comprising a calyx and similiar to a flower petal.

a division of the outer whorl (perianth

A usually showy part of the outer portion of a flower that is not differentiated into a sepal or petal.

(botany) One of the component parts of the perianth, the outermost whorls of flower parts, especially when the perianth is not divided into two whorls of unequal appearance.