Definition of "trilling"

It was pretty close quarters, but I had conversed with her at such length during the nest-building time, that she knew my voice and soon began to answer me in low trillings — trillings that could scarcely be heard — and turn her head to look at me in a friendly way.

1906, Jennie Brooks, “ways of the Kentucky Cardinal”, in Harper's Monthly Magazine, volume 112, number 670, page 627

During the singing act these wing surfaces are moved rapidly on each other, producing the familiar strident trillings of midsummer.

1910, Proceedings of the Entomological Society of Washington

Diametrically opposed rays of these stellate groups are of the same optical orientation and the twins are, therefore, trillings ( fig. 29 ).

1966, Geological Survey Professional Paper - Issues 509-510, page 55

Chrysoberyl is orthorhombic in symmetry. Like many orthorhombic minerals, it readily forms an intergrowth with two other individual crystals to make trillings with six sides or, at least, V-shaped twins.

1974, Mineral Digest, volumes 6-8, page 148

In the embryonic stage, pseudohexagonal trillings resemble those of the post-embryonic stage (Figure 2D,E), and are 1 to 3 μm in diameter.

2013, Federico Olóriz, Francisco J. Rodríguez-Tovar, Advancing Research on Living and Fossil Cephalopods, page 235

Every 67th lying-in woman has twins, every 5333rd has trillings, and only every 150,000th has fourlings.

1842, “Sweden as it is; Moral, Political and Statistical”, in The Foreign Quarterly Review, volume 28, number 55, page 449

this breed is prominent for its remarkable fecundity and yield of milk; as a rule, this goat litters once a year and drops 2 kids; occasionally trillings and fourlings.

1922, The Goat World, Devoted to the Upbuilding of the Goat Industry, page 67

About twins and trillings.

1926, Medicina fennica - Volumes 1-5, page 14