Morfem, adalah satuan bentuk terkecil dalam sebuah bahasa yang masih memiliki arti dan tidak bisa dibagi menjadi satuan yang lebih kecil lagi.
- Bentuk-bentuk yang berulang-ulang muncul dan mempunyai pengertian sama, termasuk morfem yang sama. Contoh: menjalankan, berjalan, perjalanan, dijalankan.
- Bentuk-bentuk yang mirip (hampir sama) yang mempunyai pengertian yang sama termasuk morfem yang sama, apabila kondisinya atau sebab perbedaanya dapat diterangkan secara fonologis. Contoh: impossible, inconventional, irreguler.
- Bentuk-bentuk yang mirip (hampir sama) yang mempunyai pengertian sama, termasuk morfem yang sama, apabila kondisinya atau sebab perbedaanya dapat diterangkan secara morfogis. Contoh:beranjak, belajar, beternak.
- Bentuk-bentuk yang sama merupakan morfem yang berbeda apabila berbeda pengertiannya. Di dalam semantik bentuk semacam ini disebut homonim. Contoh: bisa ular, bisa membaca.
- Bentuk-bentuk yang sama merupakan morfem yang sama, apabila pengertiannya berhubungan dengan distribusi yang berbeda. Di dalam semantik bentuk semacam ini disebut polisemi. Contoh: kepala sekolah, kepala kantor, sakit kepala.
- Apabila suatu bentuk terdapat di dalam kombinasi satu-satunya dengan bentuk lain yang pada gilirannya dapat berdiri sendiri atau dalam kombinasi dengan bentuk-bentuk lain, maka bentuk tersebut dapat disebut morfem juga (morfem unik). Contoh: beras petas, sayur mayur.
- Apabila di dalam suatu deretan struktur terdapat perbedaan yang tidak terwujud (berupa kekosongan), maka kekosongan itu dianggap morfem kosong (morfem zero).
Morpheme, is the smallest unit of form in a language that still has meaning and can not be divided into smaller units.
Linguistics is the science that studies language scientifically. Linguistic science has a clear object, namely human language. Language has a vital role in social interaction. Something is experienced, lived, felt, and thought by someone can be expressed in the form of language. The language used to interact with human beings have a variety of forms. Language is formed from the convention in the language the user community. Therefore, the science of linguistics has a variety of methods to study these languages with different purposes.
Language continues to evolve. In this case the linguistic role is to describe a system of language. Linguistics also plays a role in predicting developments in a language, so that the deviations that occur in the use of language can be fixed.
In linguistics there are sciences that form the levels or hierarchies of language, ie phonology, syntax, and morphology. Phonology is the field of linguistics that studies the sounds of a particular language according to its functions to distinguish lexical meaning in that language. Syntax is the field of linguistics which investigates all inter-relationships between words and phrases in a sentence. While the morphology is the field of linguistics is that studies the composition of parts of words grammatically.
We can study the processes of the occurrence of words, word forms, by studying the morphology and function. In terms of morphology known morpheme. Morpheme is the smallest unit of language whose meaning is relatively stable and can not be divided into smaller meaningful parts (Harimurti Kridalaksana, Dictionary of Linguistics, 2001: 141). The discussion this time will be focused on the part of the science of morphology to discuss morphemes and morphological processes in a language.
As mentioned above, the morpheme is the smallest unit of language whose meaning is relatively stable and can not be divided into smaller meaningful parts. To better know and understand the morpheme, translated morpheme recognition principles as follows:
1. The forms which appear repeatedly and have the same understanding, including the same morpheme. Examples: running, walking, travel, run.
2. The forms are similar (almost identical) that have the same sense, including the same morpheme, if the condition or because the difference can be explained phonologically. Example: impossible, inconventional, irreguler.
3. The forms are similar (almost identical) that have the same understanding, including the same morpheme, if the condition or because the difference may be explained by morfogis. Example: moving, learning, livestock breeding.
4. The same shapes are different when different morpheme understanding. On the semantics of this kind is called homonym. Example: snake venom, can be read.
5. The same forms are the same morpheme, if the meaning associated with different distributions. On the semantics of this kind is called polysemy. Example: the school principal, head office, headaches.
6. If a form contained in the only combination with another form which in turn can stand alone or in combination with other forms, the form also can be called morpheme (morpheme unique). Example: corn, vegetables.
7. If in a row there is a different structure that does not materialize (in the form of vacancies), then the morpheme is considered void empty (zero morpheme). 
Structurally, morphemes can be divided into several types, ie free morphemes, bound; origin, suplement; whole, is divided. 
Distinguished as a free morpheme and morpheme morpheme. Free morpheme can "stand alone", ie there can be a "word", and that there is no morpheme as a word but always coupled with one or more other morphemes into single words. [Three] Example: hate, drink, and one is free morpheme, while the created is too morpheme.
Free forms usually have lexical meaning, while the bound form usually has no lexical meaning but has a grammatical meaning. There is also a bound form which has lexical meaning. Free forms which have no lexical meaning is called particles. Bound forms that have a lexical meaning called klitik. 
Furthermore morpheme morpheme is divided into the origin and recharge. Morpheme morpheme origin is a form of basic word affix is attached. While additive is called a morpheme affix. For example in the word night, the night is long and morphemes are morphemes affix to.
Longer be distinguished morpheme morpheme morpheme intact and divided. For example the conjunction as the base intact. The word sustainability consists of additive divided into-.-An and pradasar morpheme (morpheme which requires pengimbuhan or pengklitikan or compounding to be free form): continuous, consisting of grafted become divided because of the additive in the form of the infix-in-.  Definition: morphemes that do not have the potential to stand alone and are always bound to other morphemes to form utterances, eg, to, to, the