Mae rhai arddodiaid yn rhedeg i ddynodi person a rhif. Mae 'am' yn un ohonyn nhw. Dyma ffurfiau rhediadol 'am':
| amdanaf i | about me | amdanon ni | about us |
| amdanat ti | about you | amdanoch chi | about you |
| amdano fe | about him | amdanyn nhw | about them |
| amdani hi | about her |
Mae rhai ffurfiau berfol yn cael eu dilyn gan am:
| Meddwl am [to think about] | Mae e'n meddwl amdani | He is thinking about it/her |
| Poeni am [to worry about] | Roedden nhw'n poeni amdani hi | They were worried about her |
| Chwilio am [to search for] | Roedd rhaid i mi chwilio amdano | I had to search for him |
|
Breuddwydio am [to dream about] |
Breuddwydiaf amdanat ti heno | I'll dream about you tonight |
| Cosbi am [to punish for] | Cafodd e ei gosbi am ddwyn | He was punished for stealing |
| Gofalu am [to care for] | Pwy sy'n gofalu amdanyn nhw? | Who is looking after them? |
| Sôn am [to mention] | Gofiaist ti sôn am y parti? | Did you remember to mention the party? |
| Pryderu am [to worry about] | Bydd hi'n pryderu amdanon ni | She will be worried about us |
Ystyron 'am'
Mae gan y rhan fwyaf o arddodiaid fwy nag un ystyr. Dyma rai o ystyron mwyaf cyffredin 'am':
1. Gall olygu 'to want' a 'to intend'
| Ydych chi am fynd yn gynnar? | Do you want to go early? |
| Beth rydych chi am ei wneud? | What do you intend doing? |
2. Gall olygu 'at' wrth sôn am amser:
| Daeth e am bedwar o'r gloch | He came at four o'clock |
3. Gall olygu 'for' wrth sôn am amser:
| Buon ni'n dawnsio am dair awr | We danced for three hours |
4.Gall olygu 'on' wrth drafod dillad
| Gwisgwch eich esgidiau amdanoch! | Put your shoes on! |
5. Gall olygu 'what...!'
| am barti | What a party! |
| am gwestiwn! | What a question! |
6. Gall olygu 'around'
| Roedd gwregys fawr am ei chanol | There was a big belt around her waist |
7. Gall olygu 'because'
| Am ei bod yn wlyb, aethon ni mewn tacsi | Because it was wet we went in a taxi |
Sylwch ar y dywediadau hyn sy'n cynnwys 'am'
| am wn i | as far as I know |
| am byth | for ever |
| am ddim | free |
| am unwaith | for once |
| am y tro | for the time being |
| cael hwyl am ben | to make fun of |
| chwerthin am ben | to laugh at |