see examples

Oxford Duden German Dictionary:
ionisch Adj. [A] Ionic (dialect, order, column)

Cassell's German Dictionary:
ionisch, adj. (Geog.) Ionian, (Archit.) Ionic.

Harper Collins German Dictionary:
ionisch adj. (Archit, Poet) ionic; (Mus) ionian;

Langenscheidt, Der Große Muret-Sanders:
ionisch adj. 1. arch. Ionic: ~e Säulenordnung Ionic order [...]

http://www.wissen.de
Wörterbuch der deutschen Sprache
i|o|nisch [Adj. , o.Steig.] 1 aus Ionien stammend; ~e Säulen; ~e Tonart

http://unabridged.merriam-webster.com
Main Entry: 1ion·ic
Function: adjective
Etymology: Latin & Middle French; Middle French ionique, from Latin ionicus, from Greek inikos, from Inia Ionia + -ikos -ic [...]
2 usually capitalized : belonging to or resembling the Ionic order of architecture that is lighter and more graceful than Doric and is characterized especially by the spiral volutes of its capital -- see CAPITAL illustration

The Macquarie Dictionary
Ionic
1. Architecture denoting or relating to one of the three Greek orders (def. 34), distinguished by its slender proportions, the volutes on the capitals, and the continuous (often figured) frieze. 2. Prosody denoting or employing one of two feet consisting of two long and two short syllables: the greater Ionic, two long and two short syllables, ¯~¯~ ~ ; the lesser Ionic, two short and two long syllables, ~ ~¯~¯. 3. relating to the Ionians.

http://www.archaeonia.com/arts/architecture/s...
The Greeks developed three architectural systems, called orders, each with their own distinctive proportions and detailing. The Greek orders are: Doric, Ionic, and Corinthian.