数すう年ねん

す

う

ね

ん

Meanings

several years; a few years

Refers to an unspecified small number of years, typically more than two but not many. Common in both spoken and written Japanese.

数すう年ねんにわたって〈動どう詞し〉to do something over a period of several years
その研けん究きゅうは数すう年ねんにわたって行おこなわれた。
The research was carried out over several years.
数すう年ねんぶりに〈動どう詞し〉to do something for the first time in several years
数すう年ねんぶりに故こ郷きょうに帰かえった。
I returned to my hometown for the first time in several years.
数すう年ねん以い内ないに〈事こと〉within a few years
数すう年ねん以い内ないに新あたらしい工こう場じょうが完かん成せいする予よ定ていだ。
The new factory is expected to be completed within a few years.
数すう年ねんがかりで〈動どう詞し〉taking several years (to complete something)
数すう年ねんがかりでプロジェクトを完かん成せいさせた。
We completed the project after several years of work.

数すう年ねん間かん
数年間 explicitly marks the span as a duration ('a period of several years'), while 数年 can simply modify a following noun without emphasizing 'period'.
数すう年ねん来らい
数年来 means 'for the past several years' and describes something ongoing since then, whereas 数年 is a neutral time span that can refer to past, present, or future.

数すうヶか月げつN3
数ヶ月 looks similar to 数年 (数＋counter) but refers to a period of several months, a much shorter span than 数年's several years.
何なん年ねん
何年 asks or expresses an unknown number of years ('how many years'), while 数年 states a definite, small, but unspecified number of years.

Compound of 数 (すう, 'several') and 年 (ねん, 'year'). The reading すうねん follows standard on'yomi.