task
noun
tɑːsk 
tæsk 
1 a piece of work that somebody has to do, especially a hard or unpleasant oneto perform/carry out/complete/undertake a taska daunting/an impossible/a formidable/an unenviable, etc. taska thankless task (= an unpleasant one that nobody wants to do and nobody thanks you for doing)Our first task is to set up a communications system.Detectives are now faced with the task of identifying the body.Getting hold of this information was no easy task (= was difficult).It was my task to wake everyone up in the morning.2 an activity which is designed to help achieve a particular learning goal, especially in language teachingtask-based learningIdioms
take somebody to task (for/over something)
to criticize somebody strongly for something they have done
The local newspaper has been taking the city council to task over its transport policy.
Usage note: taskduties mission job choreThese are all words for a piece of work that somebody has to do.task a piece of work that somebody has to do, especially a difficult or unpleasant one: Our first task will be to set up a communications system.duties tasks that are part of your job: Your duties will include setting up a new computer system.mission an important official job that a person or group of people is given to do, especially when they are sent to another country: They undertook a fact-finding mission in the region.job a piece of work that somebody has to do: I've got various jobs around the house to do.task or job?A task may be more difficult than a job and require you to think carefully about how you are going to do it. A job may be something small that is one of several jobs that you have to do, especially in the home; or a job can be something that takes a long time and is boring and/or needs a lot of patience.chore a task that you have to do regularly, especially one that you do in the home and find unpleasant or boring: household choresthe task/mission/job/chore of (doing) something(a) daily/day-to-day task/duties/job/chore(a) routine task/duties/mission/job/chore(a/an) easy/difficult task/mission/job(a) household/domestic task/duties/job/choreto do a task/a job/the choresto finish a task/a mission/a job/the choresto give somebody a task/their duties/a mission/a job/a chore