Unceasing; SYN. enduring, imperishable.

ETYM Latin consistens, p. pr.: cf. French consistant.
1. Marked by an orderly, logical, and aesthetically consistent relation of parts; SYN. logical, ordered, orderly.
2. The same throughout in structure or composition; SYN. uniform.
3. (Sometimes followed by 'with') In agreement or consistent or reliable.

ETYM Latin perennis that lasts the whole year through; per through + annus year. Related to Per-, and Annual.
1. Recurring again and again; SYN. recurrent, repeated.
2. Lasting an indefinitely long time; suggesting self-renewal.
3. (Botany) Lasting three seasons or more.

ETYM Latin persistens, -entis, p. pr. of persistere. Related to Persist.
1. Never-ceasing; SYN. relentless, unrelenting.
2. (Biology) Retained; not shed; SYN. lasting.

(Used in combination or as a suffix) Able to withstand

1. Established in a desired position or place; not moving about.
2. Established or decided beyond dispute or doubt.
3. Not changeable.

1. Seemingly uninterrupted; SYN. perpetually.
2. Without interruption.
3. Without variation or change.

In an invariable manner.

In a perennial manner; repeatedly.