coron, coroll- +

(Latin: garland, wreath, crown; from a Greek source meaning, "anything curved; a wreath, a garland")

corona
1. A faintly colored luminous ring appearing to surround a celestial body visible through a haze or thin cloud, especially such a ring around the moon or sun, caused by diffraction of light from suspended matter in the intervening medium.
2. The luminous irregular envelope of highly ionized gas outside the chromosphere of the sun.
3. In architecture, the projecting top part of a cornice.
4. In anatomy, the crown-like upper portion of a bodily part or structure; such as, the top of the head.
5. In botany, a crown-shaped, funnel-shaped, or trumpet-shaped outgrowth or appendage of the perianth of certain flowers; such as, the daffodil or the spider lily which is also called "a crown".
6. In electricity, a faint glow enveloping the high-field electrode in a corona discharge, often accompanied by streamers directed toward the low-field electrode.
coronal
1. Characterized by, or relating to, a corona; especially, of the head.
2. Relating to, or having the direction of the coronal suture or of the plane dividing the body into front and back portions.
3. In linguistics, articulated by raising the blade of the tongue, as with "t" in "tip" and "n" in "night".
coronation
1. The act or ceremony of crowning a sovereign (king or queen) or another soverign.
2. The ceremony of installing a new monarch.
coronogram
A photograph of the corona obtained by photographing the sun’s corona in full sunlight.
coronoidectomy
The surgical removal of the coronoid process (sharp triangular projection from a bone) of the mandible (jaw bone).
electric corona, corona discharge
A discharge of electricity appearing as a bluish-purple glow on the surface of and next to a conductor when the voltage gradient exceeds a certain critical value resulting from the ionization of the air in the area around the high voltage.
Finis coronat opus.
The end crowns the work.

A reference to the completion of a major project in which someone rejoices in its final accomplishment.

geocorona
1. The outermost region of the earth's atmosphere, reaching to a height approximately 15 times the radius of the earth and consisting mainly of hydrogen.
2. An envelope of ionized gases, mainly hydrogen, which encircles the earth to about 15 earth radii and emits Lyman-alpha radiation in the presence of sunlight which refers to a radiation emitted by hydrogen associated with the spectral line in the Lyman series (group of lines in the ultraviolet spectrum of hydrogen) whose wavelength is 121.5 nanometers.
Scuto bonae voluntatis tuae coronasti nos.
With the shield of Thy good-will Thou hast covered us.

Motto of the State of Maryland, U.S.A. Also translated as, "With favor wilt Thou encompass us as with a shield."