1. A piece of work assigned or done as part of ones duties.
2. A difficult or tedious undertaking.
3. A function to be performed; an objective.
tr.v.tasked, task·ing, tasks
1. To assign a task to or impose a task on.
2. To overburden with labor; tax.
Idiom:
take/call/bringto task
To reprimand or censure.
[Middle English taske, imposed work, tax, from Old North French tasque, from Vulgar Latin *tasca, alteration of *taxa, from Latin taxre, to feel, reproach, reckon; see tax.]
Synonyms: task, job1, chore, stint1, assignment These nouns denote a piece of work that one must do. A task is a well-defined responsibility that is usually imposed by another and that may be burdensome: I stayed at work late to finish the task at hand. Job often suggests a specific short-term undertaking: did little jobs about the house with skill (W.H. Auden). Chore generally denotes a minor, routine, or odd job: The farmers morning chores included milking the cows. Stint refers to a persons prescribed share of work: Her stint as a lifeguard usually consumes three hours a day. Assignment generally denotes a task allotted by a person in authority: His homework assignment involved writing an essay.
task /tsk/ n.1 an assignment, job to be performed: His boss gives him specific tasks to do each week.2to take s.o. to task: to reprimand, criticize: When he doesnt work hard, his boss takes him to task.
sk/ n. 1 an assignment, job to be performed: His boss gives him specific tasks to do each week. 2 to take s.o. to task: to reprimand, criticize: When he doesnt work hard, his boss takes him to task. 
sk)
re, to feel, reproach, reckon; see tax.]