How to Use ‘Dros / Tros’ in Welsh

Dros is a common preposition in Welsh. While it is most frequently translated as “over” or “across,” it has a variety of other uses that can sometimes trip learners up.

There is also the form tros, which is occasionally used, and means the same thing as dros. Generally, dros is far more common than tros

Today, I want to clarify exactly how and when to use these words. 

Conjugation of ‘dros

Like many Welsh prepositions, dros must be conjugated when it comes before a personal pronoun. 

Here is the conjugation table for dros:

WelshEnglish 
drosta(f) iover me, for me, etc.
drosot tiover you, for you, etc. 
drosto fe/foover him, for him, etc. 
drosti hiover her, for her, etc. 
droston niover us, for us, etc. 
drostoch chiover you, for you, etc. (plural) 
drostyn nhwover them, for them, etc. 

And remember, as dros is a preposition, it causes a soft mutation to the word immediately following it.

  • Bwrdd (table) → Dros fwrdd (Over a table).
  • Mynydd (mountain) → Dros fynydd (Over a mountain).

Adverbial forms: drosto and drosodd 

There are special ‘adverbial’ forms drosto and drosodd. Note this drosto is different from the drosto from the table above meaning ‘over him’. 

These forms drosto and drosodd are interchangeable. They are adverbial forms of ‘dros’ used for a few main functions: 

1. Number of times over 

  • Dywedais wrtho tair gwaith drosodd. = I told him three times over. 

2. Turn over, switch over, etc. (with phrasal verbs) 

Drosto and drosodd are often used after a verb to make phrasal verbs like ‘turn over’, ‘switch over’ and so on. 

  • Gelli di droi’r sianel drosto? = Could you turn the channel over?

3. ‘Finished’ 

In English, we often say ‘over’ to mean ‘finished’. In Welsh, we do not use ‘dros’ for this meaning, but rather drosto or drosodd

  • Mae hwnna drosodd nawr. = That’s over now. 

1. Dros = Over

Dros’ can be used to describe movement or position “over” or “across” something physically.

  • Neidiodd y gath dros y wal. = The cat jumped over the wall.
  • Mae’r bont dros yr afon. = The bridge is over the river.
  • Edrychodd dros ei ysgwydd. = He looked over his shoulder.
  • Mae hi’n byw dros y ffordd. = She lives across the road.

This sense of “over” also extends to “all over” when describing a large area: 

  • Mae hi yn y newyddion dros y byd i gyd. = It’s in the news all over the world. 
  • Mae glaw’n disgyn dros Gymru. = Rain is falling (all) over Wales. 

This includes: 

1) ‘Over’ an amount

  • Mae dros mil o bobl yn y gyngerdd. = There are over a thousand people at the concert. 

2) ‘Rather than’ 

  • Dewisais i goffi dros de. = I chose coffee rather than (over) tea.

3) ‘Over’ a time period

  • Beth wnest ti dros y penwythnos? = What did you do over the weekend?
  • Bydd hi’n aros dros y Nadolig. = She will stay over Christmas.
  • Dros y blynyddoedd… = Over the years…

4) ‘Divided by’ 

In mathematical terms, dros is the word used for division (referencing one number sitting “over” another in a fraction).

  • Deg dros ddau yw pump. = Ten over (divided by) two is five.

5) Other uses of ‘over’ 

Dros’ is also often appropriate for ‘over’ in a phrasal verb, like ‘look over’,‘think over’ and ‘take over’, though drosto/drosodd can also be used here. 


2. Dros = On Behalf Of 

This is a key area where learners often mistakenly use am or i. When you are doing something on behalf of, in support of, or representing someone or something, you should use dros.

Here are some examples:

  • Mae e’n chwarae dros Gymru. = He is playing for Wales.
  • Mae hi’n Ysgrifennydd dros yr Amgylchedd. = She is the Secretary for the Environment.
  • Pwy sy’n gyfrifol dros hyn? = Who is responsible for (has responsibility for) this?
  • Mae e’n gweithio dros yr achos. = He is working in support of the cause.
  • Wnei di fynd i’r cyfarfod drosta i? = Will you go to the meeting instead of me? (on my behalf)
  • Gwela dros dy hun! = See for yourself! 

It can also be used to mean ‘in favour of’, for example as in dadleuon dros annibyniaeth (arguments in favour of independence), although ‘o blaid’ is also common here. 


Useful Phrases using ‘Dros

There are several idioms and fixed phrases involving dros that are well worth adding to your vocabulary.

Drosodd a throsodd; drosto a throsto

Meaning: Over and over

  • Mae e’n dweud yr un peth drosodd a throsodd. = He says the same thing over and over.

Note that the aspirate mutation here should technically be applied to any instance of dros. For example: 

  • Rydyn ni’n ymladd dros ein gwlad a thros ein hawliau. = We are fighting for our country and our rights. 

Dros ben

Meaning: Extremely / Indeed (literally: “over head/top”). It can also mean “left over.”

  • Mae’r bwyd yn dda dros ben. = The food is extremely good.
  • Oedd unrhyw fwyd dros ben? = Was there any food left over? 

Dros ben llestri

Meaning: Over the top / Excessive (literally: “over the top of dishes/vessels”).

  • Roedd ei ymateb yn dros ben llestri. = His reaction was over the top.
  • Paid mynd dros ben llestri. = Don’t go over the top. 

Dros ei ben a’i glustiau

Meaning: Head over heels / Deeply involved (literally: “over his head and his ears”).

  • Mae e dros ei ben a’i glustiau mewn cariad. = He is head over heels in love.
  • Mae hi dros ei phen a’i chlustiau mewn dyled. = She is up to her eyes (deeply) in debt.

Tros- as a prefix 

Tros- also appears as a prefix meaning ‘over’ or ‘trans-’ in words such as: 

trosglwyddo – to transfer 
trosffordd – flyover, overpass
troslun – transfer (picture, design, etc.)


About The Author

Joseff Jones (Joe) is a freelance Welsh and Japanese tutor from Aberystwyth. Graduating from Oxford with a BA in Japanese with Chinese, Joe is now a full-time language tutor and writer with interests in second-language acquisition, linguistics, psychology and AI.