Difference of 減量 and 減少


What is the difference between 減量 and 減少? What about 増量 and 増加?

I found these following examples on my workbook, but there is no explanation
whatsoever about how to use them.

> 人口が減少する。  
>  甘くしたいので砂糖を増量する。

Thank you in advance!  
I'm new to the site, but I've learnt a lot from this community. Thanks!




`減量` refers to tangible things you can weigh or count - objects in the real
world which have weight. `減少` is a broader term which includes physical
objects but also abstract concepts.

The key to understanding the subtle difference lies in the kanji. Of course
the kanji `減` remains constant, so the difference is between `少` (few, little)
and `量` (amount, quantity).

When we check definitions of these words, we can see that `減量`
[(definition)](https://kotobank.jp/word/%E6%B8%9B%E9%87%8F-493297) tends to
refer to actual physical things, like reducing a quantity of objects, reducing
body weight, reducing the weight of something in a recipe. On the other hand,
`減少` ([definition)](https://kotobank.jp/word/%E6%B8%9B%E5%B0%91-492286) is a
more general word which is a reduction in anything. This might include actual
physical objects as above, but it also includes abstract reductions as well,
such as a reduction in working hours or a decrease in population.

The same principle applies to `増量` (an increase in quantity or weight) and
`増加` (a general increase including abstract concepts). There are many words in
Japanese which have similar meanings, but often the kanji can give us subtle
clues as to what the deeper distinctions between them are.

So always check the kanji :)




`減量` refers to tangible things you can weigh or count - objects in the real
world which have weight. `減少` is a broader term which includes physical
objects but also abstract concepts.

The key to understanding the subtle difference lies in the kanji. Of course
the kanji `減` remains constant, so the difference is between `少` (few, little)
and `量` (amount, quantity).

When we check definitions of these words, we can see that `減量`
[(definition)](https://kotobank.jp/word/%E6%B8%9B%E9%87%8F-493297) tends to
refer to actual physical things, like reducing a quantity of objects, reducing
body weight, reducing the weight of something in a recipe. On the other hand,
`減少` ([definition)](https://kotobank.jp/word/%E6%B8%9B%E5%B0%91-492286) is a
more general word which is a reduction in anything. This might include actual
physical objects as above, but it also includes abstract reductions as well,
such as a reduction in working hours or a decrease in population.

The same principle applies to `増量` (an increase in quantity or weight) and
`増加` (a general increase including abstract concepts). There are many words in
Japanese which have similar meanings, but often the kanji can give us subtle
clues as to what the deeper distinctions between them are.

So always check the kanji :)

