Ground substance is the background material within which all other connective tissue elements are embedded. In ordinary connective tissue, the ground substance consists mainly of water whose major role is to provide a route for communication and transport (by diffusion) between tissues.
Definitions for tiredness. Here are all the possible meanings and translations of the word tiredness. Princeton's WordNet(0.00 / 0 votes)Rate this definition: fatigue, weariness, tiredness(noun) temporary loss of strength and energy resulting from hard physical or mental work. he was hospitalized for extreme fatigue; growing fatigue was apparent from the decline in the execution of their athletic skills; weariness overcame her after twelve hours and she fell asleep.
Absent-mindedness is a mental condition in which the subject experiences low levels of attention and frequent distraction. Absent-mindedness is not a diagnosed condition but rather a symptom of boredom and sleepiness which people experience in their daily lives.