لَفْظٌ

Any word uttered by humans is called a لَفْظٌ.

If لَفْظٌ has a meaning, it is called مَوْضُوْعٌ (meaningful), and if it does not have any meaning, it is called مُهْمَلٌ (meaningless).

مُهْمَلٌ

Examples of لَفْظٌ مُهْمَلٌ (a meaningless word) are things like coughing, yawning, or any sound you make that doesn’t carry a real meaning.

In Arabic لَفْظٌ مَوْضُوْعٌ (meaningful word) are of two types:

مُفْرَدٌ (singular) : It is that single word, which conveys one meaning. It is also called كَلِمَةٌ .
مُرَكَّبٌ (compound) : It is a group of words. They may form a complete sentence or an incomplete one.