ちょっと一杯[chottoippai] let's have a quick drink
ばつ一[batsuichi] being once divorced
一向[hitaburu] nothing but
サラダ一皿[saradahitosara] plate of salad

安全第一[anzendaiichi] safety first
一か八か[ichikabachika] sink or swim
一っ走り[hitoppashiri] spin (as in 'take a car for a spin')
一つ一つ[hitotsuhitotsu] one-by-one

ローム層[roomusou] stratum of loam
亜成層圏[aseisouken] substratosphere
一層[issou] much more
沖積層[chuusekisou] alluvium
下層[kasou] lower strata (classes)

下層階級[kasoukaikyuu] proletariat
下層社会[kasoushakai] the underworld
下層土[kasoudo] subsoil
化石層[kasekisou] fossil bed
階層[kaisou] class

御目出度う御座います[omedetougozaimasu] congratulations
駄目になる[dameninaru] to spoil
繋ぎ目[tsunagime] joint
軽目焼[karumeyaki] hard caramelized sugar candy
駄目押し[dameoshi] making doubly sure

一つ目[hitotsume] one-eyed
一合目[ichigoume] the start of a climb up a hill
一丁目[icchoume] Block 1
ひと目[ichimoku] (a) glance
一目惚れ[hitomebore] to be taken with someone at first sight (similar to "love at first sight", but not as strong)