centi-, cent-

(Latin: hundred; a decimal prefix used in the international metric system for measurements)

This prefix is used in the metric [decimal] system as, one-hundredth [U.S.] and hundredth [U.K.], and denotes 1/100th of a unit or 10-2 [0.01]. The metric symbol for centi- is c.

per centum, per cent
By the hundred.
percent, per centum, %
One part in every hundred.

A quantity can be increased by any percentage but should not be decreased by more than 100 percent.

Once sales have been reduced by 100 percent, for example, it ceases to exist. In defiance of this logic, however, advertisers sometimes refer to a 150 percent decrease in new luggage prices or a new medication that increases energy by over 300 percent.

It is assumed that what is implied by the last example is that the new medicine is three times as effective as some other medicine, but such constructions are still considered to be etymologically incorrect because 100 percent is the
total amount of anything.

percentage (s) (noun), percentages (pl)
1. A proportion stated in terms of one-hundredths that is calculated by multiplying a fraction by 100: If all of the apples were picked, if would be 100%, whereas if only half of the amount of apples were picked, it would be 50%, and if none of the apples were picked, 0% of the apples were picked.
2. A proportion or share in relation to a whole; a part: The hecklers constituted only a small percentage of the audience."
3. An amount, such as an allowance, duty, or commission, that varies in proportion to a larger sum, for example, total sales: They are working for a percentage of the gross sales.

When preceded by "the", percentage takes a singular verb:

The percentage of unskilled workers is relatively small.

The percentage of errors in his term paper is excessive.

When preceded by "a", percentage takes either a singular or plural verb, depending on the number of the noun in the prepositional phrase that follows:

A small percentage of the new workers are unskilled.

A large percentage of the crop was lost because of the lack of rain.

A large percentage of the electorate still remains undecided.

1. In statistics, a value on a scale of one hundred that indicates whether a distribution is above or below it.
2. One of a set of points on a scale arrived at by dividing a group into parts in an order of magnitude.

For example, a score equal to or greater than 97 percent of those attained on an examination is said to be in the 97th percentile.

Relating to a 400th anniversary.
A 500th anniversary.
sesquicentennial (adjective) (not comparable)
Referring to a period of 150 years or pertaining to something that occurs every 150 years; relating to or happening after a period of 150 years.
supercentenarian, super-centenarian
A supercentenarian is someone who has reached the age of 110 years or more, something achieved by only one in a thousand centenarians.

About one supercentenarian in fifteen lives to 114 years or more. The term has been around from around the 1970s and was further popularized in 1991 by William Strauss and Neil Howe, in their book Generations.

Early references tend to mean simply "someone well over 100" but the 110-and-over cutoff is apparently the accepted criterion by demographers.

1. A year, or an exact day, 300 years after an event, usually one of special historic significance.
2. Coinciding with the 300th anniversary of an event, and often celebrating or commemorating the event.

Related "metric" families: yotta; zetta; exa; peta; tera; giga; mega; kilo; hecto; deka; deci; milli; micro; nano; pico; femto; atto; zepto; yocto.