Chiefly northern. Obs. or arch. Forms: 4 firþe, fyrþe, 46 fyrth, 6 firth. [Metathesis of FRITH sb.2] A synonym of FRITH sb.2 in some of its senses: A deer-forest, hunting-ground; a piece of ground covered with brushwood with a few trees; a coppice, small wood. In poetry frequent in alliterative phrases, firth and fell, firth and field, firth and fold: see FRITH sb.2
c. 1375. Sc. Leg. Saints, Blasius, 75.
| Þane send he ma knychtis þame with | |
| To hwnt in [to] þat sammyne fyrth. | 
a. 1400[?]. Morte Arth., 1708.
| We have foundene in ȝone firthe | |
| ffifty thosandez of folke | |
| of ferse mene of armez. | 
c. 1425. Wyntoun, Cron., I. xiii. 51.
| Ðat is ane Lande of nobyl Ayre, | |
| Of Fyrth, and Felde, and Flowrys fayre. | 
c. 1475. Rauf Coilȝear, 681.
| Blyth byrdis abufe, and bestiall full bene, | |
| Fyne foullis in Fyrth, and Fischis with fry. | 
1513. Douglas, Æneis, VII. Prol., 162.
| Has thus begoune in the chyll wyntir cauld, | |
| Quhen frostis days ourfret bayth fyrth and fauld. | 
1535. Stewart, Cron. Scot., II. 593.
| That kirk or kirkmen gat of thame no girth, | |
| Moir nor the fox that rynnis in the firth. | 
1581. Savile, Agric. (1622), 192. The firths and the thickets he proued the first in his owne person.
1794. Burns, A Vision (1st version), 17.
| Now looking over firth and fauld, | |
| Her horn the pale-facd Cynthia reard; | |
| When, lo, in form of minstrel auld, | |
| A stern and stalwart ghaist appeard. |