This is the 2003rd most frequent Turkish word.
seyyanen
Equally or uniformly distributed.
The word "seyyanen" is used here to indicate a uniform or equal adjustment made across all entities, in this case, salaries.
Maaşlara seyyanen zam yapılması kararlaştırıldı.
It was decided that a uniform raise will be applied to the salaries.
In this sentence, "seyyanen" implies that the aid will be distributed equally or uniformly to all recipients.
Seçim sonrası seyyanen yardım dağıtılacak.
After the election, uniform aid will be distributed.
Here, "seyyanen" is used to describe an increase applied equally across all items or individuals subject to taxation.