hepta-, hept-

1. A group of seven or seven days: "The hebdomads are regular features of calendars around the world."

"Monday to Sunday or Sunday to Saturday are the sequences of days in a hebdomad."

2. Etymology: the number seven, from Late Latin hebdomas; which came from Greek hebdomos, "seventh"; from hepta, "seven".

Weekly: "Any hebdomadal activity takes place, appears, or is done every week."

"Janine always tried to make time to go regularly to the hebdomadal services at her local church."

A reference to a calendar week: "The family members of Bill and Lorna always tried to have a hebdomadally scheduled meal so all of them could be together."

1. A system of seven sounds: "Trudy sang a heptachord composition of seven chords or tones."
3. An ancient Greek stringed instrument: "In old Grecian times, a heptachord or a lyre with seven chords was used to present music."

1. A reference to that which exhibits seven colors: "A heptachromic spectrum presents the complete range of colors into which light can be separated when it passes through a prism."
2. Pertaining to the capability of seeing all seven colors of a spectrum: "Tamika had normal heptachromic color vision."

1. Numbers that have a total of seven: "The days of the week come in groups of heptads."
2. A group, or groups, of seven things: "Many mothers have a constant heptad of days as they take care of their children."

The presence of seven digits on the hands or the feet: "Floyd had an abnormal heptadactylia of fingers on his left hand while the other hand had a normal pentadactylia of fingers."

Having seven digits on a hand or a foot: "When a person has heptadactylism, then he or she has seven fingers on one or both hands, instead of the normal five fingers on each hand; and seven toes, instead of the normal five toes on one foot or on both feet."

A reference to the presence of seven digits on a hand or a foot; or on both hands and/or both feet: "The parents were shocked to see that their daughter, Fay, was heptadactyly born with so many toes on both of her feet."

A geometric shape with seven angles and seven sides: "The students were learning about heptagons in their math class."

A reference to a formation that has seven sides and seven angles: "Kyle had a heptagonal bedroom in his apartment."

Having seven pistils (seven female reproductive parts) of flowers: "Heptagynous blossoms have seven organs (pistils) that can receive pollen and produce fruits for plants."

Pertaining to a solid figure with seven flat sides or faces and straight edges: "A heptahedron has several different forms; in fact, heptahedra have several shapes in convex (curving or bulging outward; such as, the exterior of a sphere) and concave (curved like the inner surface of a sphere)."

A chemical compound that contains seven molecules of water: "Magnesium sulfate is one example of a heptahydrate."

1. Plants that have flowers in groups of seven whorls or circles around stems: "There are heptamerous plant parts; such as, petals or sepals."
2. Having parts that are arranged in groups of seven: "There are some other heptamerous elements, all of which are divided into seven parts."