Εννοια

1. Forms collective nouns, almost always neuter gender. Whenever possible, the root vowel is modified as well.
2. Forms action nouns, usually with a sense of repetition or continuation. All of these nouns are neuter and have no plural.
3. Forms nomina rei actae, verbal nouns that refer to the result of an action, always of neuter gender.
4. Forms past participles in combination with a suffix -en or -(e)t. Nouns are frequently made from the past participle.
5. Forms verbs with terminative aktionsart. This is hardly productive after Early New High German and outside of dialects.
6. Indicates association or togetherness; co-.