noun
Literal or historical act of cutting off a head; often used in contexts of execution or punishment.
昔の刑罰には截頭が含まれていた。
Ancient punishments included beheading.
noun
pruning; trimming plant tops
Gardening term for cutting back the top growth of plants, especially flowers and leaves, to shape them or encourage growth.
バラの截頭は春先に行うとよい。
It's good to prune roses in early spring.
Compound of 截 (cut) and 頭 (head). The gardening sense is a metaphorical extension of the literal meaning.