Criteria vs. Criterion

Criterion means a standard on the basis of which something or someone is judged or evaluated.

Criterion is the singular form whereas Criteria is the plural form.

• The committee identified five important criteria for their business plan. (plural form)
• The customer feedback is the most important criterion for us. (singular form)
• The team must satisfy all the criteria for entrance to the competition or they will be rejected. (plural form)
• Safety should be the number one criterion when one buys a car. (singular form) 
• Merit should be the sole criterion for judging students. (singular form)

Note: Phrases such as a criteria, single criteria, one criteria, or this criteria should be avoided. 

Canvas vs. Canvass

Canvas is a strong coarse unbleached cloth made from hemp, flax, or a similar yarn, used to make items such as sails and tents and as a surface for oil painting.

• In modern world, canvas is the most common form of oil painting.
• Canvas began to outdistance wood panels as the preferred medium for painters in northern Europe around the 17th century.
• One can enlarge pictures on canvas to look like paintings.
• The nomadic tribes dwell in large tents made of canvas or yak wool.

Canvass is to get political support from voters.  

Canvass as a verb means to examine carefully, discuss thoroughly; scrutinise; to solicit voters, orders or opinions.

• All aspects of canvass were open to public inspection.
• As always, Sam opted to canvass in his own society first.
• The issues related to child labor are thoroughly canvassed in the upcoming report.
• The local leader spent the whole month canvassing for votes.

Continual vs. Continuous

Continual and continuous are not interchangeable.

Continual means frequently repeated or recurring. It is generally used for things that happen repeatedly, often irritatingly.

• Tired of continual interruptions, he switched off his mobile.
• Her math teacher's continual remarks has impacted her learning process.
• The minister received continual complaints from the public for the government's handling of the street protests.
• A successful project is followed by continual review and embracing change.
• I can't work with these continual interruptions.

Continuous means continuing without stopping, happening or existing without a break or interruption.

• The power backup provides enough power for unto six hours of continuous use.
• It was at Frogmore that the world's first machine for making continuous roll of paper was built.
• The continuous noise from the factory nearby kept him awake all night.
• Additional leave without pay may be requested up to a continuous period of forty eight weeks.
• There has been continuous fighting on the border for last 24 hours.

Lose vs. Loose

Lose and loose are liable to be confused.

Lose is a verb. it means not able to find, not have anymore, not win or to mislay.

• Susan loses her pen at least once a week.
• Our cricket team hasn't lost a game all year.
• Sam is always losing his car keys.
• She always loses one sock.

Loose is an adjective. It means not tight or not fastened.

• My new shoes are loose.
• His pants are loose. 
• He has a loose tooth.
• He was wearing a loose shirt.

Loose can also act like a verb meaning to undo as in loose the knot of the rope or set free as in loose the pack of dogs.

• I always lose my handkerchief (correct) --> a lost handkerchief.
• I always loose my handkerchief (incorrect) --> handkerchief is less tight 

• I like my hair loose and flowing (correct) --> loosened hair.
• I like my hair lose and flowing (incorrect) --> hair loss/ lost hair

• I feel I am going to lose my job (correct) --> not have my job anymore.
• I feel I am going to loose my job (incorrect) --> absurd meaning. How can I set free my job or unfasten it.

Note: Loose and loosen are related but not lose. 
Loosen means to make less tight as in Emily has put on weight and so she has had to loosen her belt.

Altogether vs. All together

Altogether (pronoun+adverb) means jointly; collectively at the same place or in the same time.

Usage note: All together is used only in sentences that can be rephrased so that all and together may be separated by other words.

• The guests arrived all together.
• All the guests arrived together.

• The old newspapers lay all together in a heap. 
• All the old newspapers lay together in a heap.

• Sam was most happy when we were all together.
• Sam was most happy when we all were together.

Altogether (adverb) means with everything included; entirely; with all counted; all told; on the whole; completely; totally; taking everything into consideration.

• I stopped visiting her house altogether.
• We collected altogether $1000.
• Altogether it was great day.